Faculty of Physics

9 Saulėtekio, LT-10222 Vilnius

Tel. 236 6001, fax 236 6003

E-mail:

http://www.ff.vu.lt

Dean – Prof. Dr. Roaldas Gadonas

 

STAFF

75 teachers (incl. 69 holding research degree), 149 research fellows (incl. 117 holding research degree), 78 doctoral students.

DEPARTMENTS OF THE FACULTY

Experimental Nuclear and Particle Physics Centre (sui generis Department)
Institute of Chemical Physics
Institute of Photonics and Nanotechnology
Laser Research Centre
Institute of Applied Electrodynamics and Telecommunications
Institute of Theoretical Physics and Astronomy

RESEARCH AREAS

Analysis of Atoms, Subatomic Particles or their Ensembles, Complex Systems Electromagnetic Radiation and Cosmic Objects
Development, Characterization, and Interdisciplinary Application of Advanced Electronic and Optoelectronic Devices
Investigation of Novel Organic and Inorganic Functional Materials and Structures
Laser Physics and Technology
Solid State Physics and Technology
Spectrometric Characterization of Materials and Electronic/Molecular Processes

DOCTORAL DISSERTATIONS DEENDED IN 2017

V. Abramavičius. Theory of energy and charge transport in organic molecular systems.

J. Belovickis. Ultrasonic and dielectric spectroscopy of composites based on polymers and organic or inorganic Nanoparticles.

V. Chorošajev. Variational theory of electronic energy transfer and relaxation.

A. Gelžinis. Spectroscopy of photosynthetic molecular complexes.Theoretical modeling and analysis.

T. Grigaitis. Influence of doping on the optical and electrical properties of SiNx films deposited using CVD technology.

H. R. Hamedi. Linear and nonlinear phenomena for slow light.

K. Ivanauskienė. The influence of group delay dispersion of the resonator components on an optical parametric oscillator synchronously pumped by femtosecond pulses.

V. Juknevičius. Spatio-temporal behavior in continuum surface growth models.

E. Kamarauskas. Investigation of carbazole- and hydrazone-based charge carrier materials and dyes for solar cells.

R. Kazakevičius. Complex nonlinear systems affected by colored and non-Gaussian external noise.

J. Klevas. The nfluence of convection and non-local radiation field on spectral line formation in stellar atmospheres.

V. Klimavičius. Solid state NMR spectroscopy of complex innovative materials.

R. Mackevičiūtė. Electrical investigation of thin ferroelectric films and nano structures.

M. Matulionytė. Investigation of structure and spectral properties of photoluminescent gold nanoclusters and their effect on cancer cells.

E. Palaimienė. Broadband dielectric spectroscopy of relaxor and related ceramics.

D. Prakapavičius. Oxygen in stellar atmospheres: spectral line formation and abundances.

S. Raišys. Tuning exciton diffusion in organic optoeletronic materials.

L. Radžiūtė. Research on parity and time-reversal violation in atomic physics.

P. Stanislovaitis. Generation of optical vortices and their linear and nonlinear transformations.

B. Šaulys. Quality diagnostics of nitride based light emitting diodes via low frequency noise characteristics.

J. Važgėla. Charge carrier transport and recombination in bulk heterojunctions.

CONFERENCES ORGANIZED IN 2017

2nd Taiwan, Lithuania, and Latvia Workshop on Quantum and Nonlinear Optics with Rydberg-State Atoms

24th International Conference on Noise and Fluctuations

International conference Accelerating ERA Development by Promotion of Gender Eqality in STEM Research

Laserlab - Europe User Meeting

MAIN SCIENTIFIC ACHIEVEMENTS IN 2017

The first 3D hydrodynamical model of a red giant star with the chromosphere was constructed. It was shown that shock waves propagating in the chromosphere alter the intensity and shape of the chromospheric spectral line profiles, and lead to a significantly higher flux in the UV. These properties cannot be recovered using classical 1D hydrostatic model atmospheres. The obtained results demonstrate that chromospheres are prominent in red giant stars and play an important role in shaping their observable properties. The paper summarizing these results was marked as a Highlight Paper of the international journal Astronomy and Astrophysics. Prakapavičius, D., Kučinskas, A., Dobrovolskas, V., Klevas, J., Steffen, M., Bonifacio, P., Ludwig, H.-G., Spite, M. 2017. Three-dimensional hydrodynamical CO5BOLD model atmospheres of red giant stars. V. Oxygen abundance in the metal-poor giant HD 122563 from OH UV lines. Astronomy & Astrophysics, 599, A128.

By investigating triplet−triplet annihilation (TTA) mediated light upconversion (UC) in organic films we demonstrate that conversely to the common belief that poor UC efficiency in the solids is limited by inefficient triplet exciton diffusion, the dominant UC loss channel is actually caused by the quenching of long-lived triplet excitons in the emitter. We achieved one of the highest TTA-UC quantum efficiency (~3%) in the solid films by employing singlet-exciton-sink approach. The best scientific paper (2017 year VU Rector’s Award): Dr. S. Raišys, Dr. K. Kazlauskas, Prof. S. Juršėnas. The role of triplet exciton diffusion in lght-upconverting polymer glasses. ACS Appl. Mater. Interfaces 8, 15732–15740 (2016).

The photocarrier lifetime in non-crystalline systems should be viewed and treated not as a material parameter, but rather as a device parameter that can vary depending on the experimental conditions. To use the lifetime to truly understand recombination in these systems, one needs precise knowledge of the carrier mobilities and densities which is experimentally challenging. As the photocarrier lifetime is an inadequate parameter to describe the nature of recombination, it was proposed to use the bimolecular recombination coefficient instead. Pivrikas, A., Philippa, B., White, R.D., Juska, G. Photocarrier lifetime and recombination losses in photovoltaic systems. Nat. Photon. 10, 282 (2016); doi: 10.1038/nphoton.2016.78.

 

INSTITUTE OF CHEMICAL PHYSICS

3 Saulėtekio, LT-10257 Vilnius

Tel. 223 4596

E-mail:

Head – Prof. Dr. Valdas Šablinskas

DIVISION OF THEORETICAL PHYSICS

Tel. 236 6030
E-mail:

Head – Prof. Habil. Dr. Leonas Valkūnas

STAFF

Professors: Prof. Habil. Dr. L. Valkūnas (part-time), Prof. Dr. D. Abramavičius, Prof. Dr. E. Anisimovas, Prof. Dr. J. Šulskus.
Associate professors: Doc. Dr. J. Bučinskas, Doc. Dr. J. Chmeliov, Doc. Dr. K. Glemža, Doc. Dr. M. Mačernis, Doc. Dr. O. Rancova.
Lecturers: Dr. V. Butkus, Dr. A. Gelžinis, Dr. S. Toliautas.
Doctoral students: V. Abramavičius, V. Chorošajev, V. Dūdėnas, A. Gelžinis, A. Stepšys.

RESEARCH GROUPS

Modeling of Dynamic Processes in Molecular Compounds. PI: prof. Leonas Valkūnas.

Physics of Open Quantum Systems. PI: prof. Darius Abramavičius.

Quantum Chemistry. PI: prof. Juozas Šulskus.

RESEARCH INTERESTS

Characterization of the spectral properties of molecular complexes of natural and artificial origin
Theoretical studies of temperature dependences of the fluorescence kinetics of photosynthetic light-harvesting complexes from plants at different level of aggregation
Development of quantum relaxation theory and application to molecular systems
Development of the theoretical background of multi-dimensional spectroscopy of molecular complexes characterized by exciton spectra and charge-transfer states
Modeling of single molecular spectroscopy data of complex systems

RESEARCH PROJECTS CARRIED OUT IN 2017

Project Supported by University Budget

Modeling of Processes in Photoactive Organic Materials and Nanosystems. Prof. L. Valkūnas. 2011–2018.

Correlation effects of static energy disorder leading to non-Gaussian site energy distribution of statistical distribution was considered, demonstrating variability of the properties of exciton wavefunctions and consequently changes of material functional characteristics. Theoretical analysis of spectroscopic properties, excitation transfer and relaxation pathways was carried out by considering photosynthetic complexes and their aggregates. Coexistence and intermixing of electronic and vibrational coherences has been proposed to be responsible for the observed long-lived coherences and high energy transfer efficiency. It has been demonstrated by theoretically analyzing the multidimensional spectra obtained from six-porphyrin nanorings. Stochastic Schroedinger equation in phase space was developed and applied to simulate charge delocalization and relaxation dynamics in a Perovskite solar cells.

Main publications:

Gelzinis, A., Abramavicius, D., Ogilvie, J. P., Valkunas, L. 2017. Spectroscopic properties of photosystem II reaction center revisited. J. Chem. Phys., vol. 147 (11), p. 115102.

Butkus, V., Alster, J., Bašinskaitė, E., Augulis, R., Neuhaus, P., Valkunas, L.  2017. Discrimination of diverse coherences allows identification of electronic transitions of a molecular nanoring. J. Phys. Chem. Lett., vol. 8 (10), p. 2344–2349.

Rancova, O., Jakučionis, M., Valkunas, L., Abramavicius, D. 2017. Origin of non-Gaussian site energy disorder in molecular aggregates. Chem. Phys. Lett., vol. 674, p. 120–124.

Augulis, R., Franckevičius, M., Abramavičius, V., Abramavičius, D., Zakeeruddin, S. M., Grätzel, M., Gulbinas, V. 2017. Multistep photoluminescence decay reveals dissociation of geminate charge pairs in organolead trihalide perovskites. Adv. Energy Mater., 1700405.

National Research Projects

Research Council of Lithuania. Dynamics of Photoinduced Processes in Proteins and Model Systems (No: MIP-080/2015). Prof. L. Valkunas. 2015–2018.

To get more insight into the physical origin of so-called nonphotochemical quenching mechanism taking place in photosystem II of green plants, high-resolution time-resolved fluorescence measurements of thylakoid membrans as well as single molecule spectroscopy measurements of LHCII complexes extracted from wild type plants are their mutants containing different composition of carotenoid molecules were carried out in the experimental group of the partners. Within the frame of our studies we are able to discriminate the fluorescence spectra and kinetics from photosystem I and photosystem II and associate the red-emitting state, having fluorescence maximum at ∼700 nm, with the partial mixing of excitonic and charge transfer states in LHCII complexes. Blinking fluorescence obtained from single molecule spectroscopy data are related to the quenching ability of carotenoids. Our results also show that the required level of photoprotection in vivo can be achieved by a very subtle change in the number of LHCIIs switched to the quenched state.

Quantum superposition of molecular electronic states is very fragile because of thermal energy fluctuations and the static conformational disorder induced by the intimate surrounding of constituent molecules of the system. However, the nature of the long lived quantum beats, observed in time-resolved spectra of molecular aggregates at physiological conditions, is still being debated.

Based of the crystal structural data of LHCII complexes the all pigment quatum mechanical calculations have been fufilled. We show that quenching in LHCII crystals is the result of slow energy transfer from chlorophyll to the centrally-bound luteins (Lut), predominantly the Lut620 associated with the chlorophyll ‘terminal emitter’, one of the proposed in vivo pathways. We show that this quenching is rather independent of the particular species of carotenoids and excitation ‘site’ energy. The defining parameter is the resonant coupling between the pigment co-factors. Lastly, we show that these interactions must be severely suppressed for a light-harvesting state to be recovered.

Main publications:

Fox, K. F., Balevičius, V., Chmeliov, J., Valkunas, L., Ruban, A. V., Duffy, C. D. P. 2017. The carotenoid pathway: what is important for excitation quenching in plant antenna complexes? Phys. Chem. Chem. Phys., vol. 19 (34), p. 22957–22968.

Tutkus, M., Chmeliov, J., Rutkauskas, D., Ruban, A. V., Valkunas, L. 2017. Influence of the carotenoid composition on the conformational dynamics of photosynthetic light-harvesting complexes. J. Phys. Chem. Lett., vol. 8, p. 5898–5906.

Pan, J., Gelzinis, A., Chorosajev, V., Vengris, M., Senlik, S. S., Shen, J. R., Valkunas, L., Abramavicius, D., Ogilvie, J. P. 2017. Ultrafast energy transfer within the Photosystem II core complex. Phys. Chem. Chem. Phys., vol. 19, p. 15356–15367.

Research Council of Lithuania. Development of Simulation Approaches for Coherent Time-Resolved Spectroscopy of Photoactive Molecular Systems (MIP-090/2015). Prof. D. Abramavičius. 2015–2018.

The project was targeting the nonlinear properties of molecular aggregates coupled to dissipative environmnent. Statistical analysis of microscopic origin of static disorder in a molecular aggregate was described. It was found that the statistics of transition energy fluctuations is non-gaussian and, therefore, gaussian laws of averaging do not apply. The fluctuations become inherent not only in one-excitation manifold but also in double-excitation manifold with multiple correlation configurations. This was confirmed by comparing simulated nonlinear spectroscopy simulations to experiments of baterial reaction centers at low temperature. Complicated intramolecular interactions in molecular aggerates cause correlated weakly damped dynamics that translated into spectral oscillations. That was confirmed by analysis of experimental data of molecular nanomaterial.  These complicated spectral properties come from space correlations within the nanomaterials. The second kind of nonlinearity is due to inertial nature of the vibrational environment. The relaxation of the bath modes induces breaking of symmetry of the excitonic systems what causes delayed formation of excitonic polarons. This was demonstrated by analyzing time evolution of exciton relaxation in nonlinear laser spectra of a photosystem II. Overal environment vibrational modes are nonlinear. Accurate treatment of these require including nontrivial quantum properties of the modes: such as quantum squeezing of the weakly damped oscillators and internal energy and phase relaxation. These effects are beyond complex energy relaxation pathways in carotenoid molecules that are very important for human nutrition and health. 

Main publications:

Chorosajev, V., Marciulionis, T., Abramavicius, D. 2017. Temporal dynamics of excitonic states with nonlinear electron-vibrational coupling. J. Chem. Phys., vol. 147, p. 074114.

Balevičius, V., Lincoln, C. N., Viola, D., Cerullo, G., Hauer, J., Abramavicius, D. 2017. Effects of tunable excitation in carotenoids explained by the vibrational energy relaxation approach. Photosynth Res.; doi: org/10.1007/s11120-017-0423-6.

MAIN R&D&I (RESEARCH, DEVELOPMENT AND INNOVATION) PARTNERS

Centre of Physical Sciences and Technology (Lithuania)
University of California, Berkeley, and University of California, Irvine (USA)
University of Michigan, Ann Arbor (USA)
Queen Mary University, London (UK)
Institute of Physics of Charles University (Czech Republic)
Institute of Solid State Physics, University of Latvia (Latvia)
Riga Technical University (Latvia)
Free University of Amsterdam (Netherlands)
Free University of Brussels (Belgium)
Lund University (Sweden)
Nuclear Research Centre, Saclay (France)
State key laboratory of supramolecular structure and materials, Jilin University (China)
Dalian Institute of Chemical Physics, Chineese Academy of Sciences (China)
University of Antwerp (Belgium)
University of Würzburg (Germany)
Vienna Technical University (Austria)
Institut de Biologie et de Technologie de Saclay, University Paris Sud, Gif sur Yvette (France)
N. Bogolyubov Institute for Theoretical Physics, Ukrainian Academy of Sciences (Ukraine)

OTHER SCIENTIFIC ACTIVITIES

Prof. L. Valkūnas –

• member of the Lithuanian Academy of Sciences;
• editorial board member of the Lithuanian Journal of Physics;
• vice-president of the Lithuanian Physical Society;
• doctor Philosophiae Honoris Causa of the Bogolyubov Institute for Theoretical Physics of the National Academy of Sciences of Ukraine.

 

DIVISION OF MOLECULAR SPECTROSCOPY

Tel. 223 4596

E-mail:

Head - Prof. Dr. Valdas Šablinskas

STAFF

Professors: Habil. Dr. V. Balevičius, Dr. V. Šablinskas, Habil. Dr. G. Niaura (part-time), Dr. V. Gulbinas (part-time).
Associate professors: Dr. V. Aleksa, Dr. J. Čeponkus, Dr. A. Gruodis, Dr. L. Juodis, Dr. F. Kuliešius, Dr. A. Maršalka, Dr. V. Urbonienė.
Lecturers: Dr. K. Aidas, L. Dagys, V. Klimavičius, D. Lengvinaitė, R. Platakytė, M. Velička.
Doctoral students: L. Dagys, N. Karalius, V. Klimavičius, K. Kristinaitytė, J. Kausteklis,  J. Lach, D. Lengvinaitė, R. Platakytė, S. Tamošaitytė, M. Velička.

RESEARCH INTERESTS

Spectroscopy of molecules and condensed matter
IR, UV, Raman, NMR studies of organic compounds of the organized structures in the liquid, solid phases and nano-crystals

SERS studies of traces of biologically active molecules in biological fluids
Phase transitions and critical phenomena
Molecular interactions, hydrogen bonding, conformational analysis
Spectral markers in biological tissues and fluids
Matrix isolation FTIR spectroscopy

RESEARCH PROJECTS CARRIED OUT IN 2017

Project Supported by University Budget

Spectroscopy of Hybrid and Structured Functional Materials and Coatings for Photonic Devices and Optical Sensors. Prof. V. Sablinskas, Prof. V. Balevicius. 2017.

Planned activities: Studies of molecular diffusion and relaxation in nanostructures by means of NMR CP kinetics and Raman spectroscopy. Elaboration of diagnostic tools for biological tissues based on Raman and infrared spectroscopic techniques. Developing of spectral systems for in situ and in vivo diagnostics of the tissues. Conformational analysis of heterocyclic molecules by means of vibrational spectroscopy, studies of internal hydrogen by means of Raman matrix isolation technique.

Achievements: The measurements of 1H-11B CP kinetics upon MAS of [bmim][BF4] confined in mesoporous SBA-15 and MCM-41 were carried out. The complex shaped 11B CP MAS signals were observed in both silica and were decomposed into two Lorentz components. This points towards the possibility of bimodal distribution of [bmim][BF4] in the studied confinements. The convergence of classical and non-classical spin coupling models was deduced processing CP kinetic curves. The convergence of spin coupling models was discussed in terms of relatively high mobility of BF4– anion respect to the cation and the dynamics of anions in pores. The spin diffusion along the pore surfaces in MCM-41 is more than twice faster than in SBA-15. Nd3+-doped yttrium aluminium garnet and Eu3+–Nd3+-co-doped yttrium aluminium garnet were studied using solid state NMR. The local environments of Eu3+ and Nd3+ activator ions of the garnets structure compounds were determined from Al27 NMR MAS spectra. Methods on nonlinear vibrational spectroscopy were applied for studies of urinary stones. The method for identification of cancerous cells in the kidney tissue based on the study of tissue smears SERS and ATR FTIR spectra was elaborated. This method enables an expansion of spectroscopic diagnostic to direct in vivo studies with the use of waveguide optics. Such an experimental system based on portable IR spectrometer, IR region waveguide and changeable micro ATR crystal is developed in our laboratory in cooperation with Optics Company Art Photonics, Germany. Matrix isolation FTIR studies of heterocyclic molecules were carried out. The current system of matrix isolated samples was adopted to be suitable for the Raman spectroscopic studies. The Raman spectra of argon and nitrogen isolated acetylacetone and its chlorinated and fluorinated derivatives were recorded and interpreted. The strength of internal hydrogen bond was evaluated based on the spectral bands positions in different structures. The spectra of chlorinated malonaldehyde isolated in argon were measured and the results were used as additional argument for hydrogen tunneling along hydrogen bond in the matrix isolated chlorinated malonaldehyde.

Main publications:

Klimavičius, V., Dagys, L., Chizhik, V., Balevičius V. 2017. CP MAS kinetics study of ionic liquids confined in mesoporous silica: convergence of non-classical and classical spin coupling models. Applied Magnetic Resonance, vol. 48, p. 673–685.

Pavasaryte, L., Katelnikovas, A., Klimavicius, V., Balevicius, V., Krajnc, A., Mali, G., Plavec, J., Kareiva A. 2017. Eu3+-doped Y3-xNdxAl3O12 garnet: synthesis and structural investigation. Phys. Chem. Chem. Phys., vol.19, p. 3729–3737.

Velicka, M., Urboniene, V., Ceponkus, J., Pucetaite, M., Jankevicius, F., Sablinskas, V. 2017. Detection of cancerous kidney tissue by means of SERS spectroscopy of extracellular fluid. J Raman Spectrosc., vol. 48, p. 1744–1754.

Pucetaite, M., Tamosaityte, S., Galli, R., Sablinskas, V., et al. 2017. Microstructure of urinary stones as studied by means of multimodal nonlinear optical imaging. Journal of Raman Spectroscopy, vol. 48, iss. 1, p. 22–29.

National Research Projects 

Research Council of Lithuania. National program Healthy aging. Spectroscopic Express Analyzer of Cancerous Tissue (No. SEN-15053). Prof. V. Šablinskas. 2015–2018. 

Achievements:  New spectroscopic method for characterization of cancerous kidney tissue was developed. Infrared optical fiber based ATR sensor for spectroscopic in situ characterization of extracellular fluid was designed and tested. Patent application for the sensor was accepted by National patent biuro (reg. nr. LT2017504).

Main publications:

Velicka, M., Urboniene, V., Ceponkus, J., Pucetaite, M., Jankevicius, F., Sablinskas, V. 2017. Detection of cancerous kidney tissue by means of SERS spectroscopy of extracellular fluid. J Raman Spectrosc., vol. 48, p. 1744–1754.

Velička, M., Radžvilaitė, M., Čeponkus, J., Urbonienė, V., Pučetaitė, M., Jankevičius, F., Steiner, G. 2017. Proceedings of SPIE. Spie, vol. 10068, 100681W, p. 1–9.

International Research Projects 

Research Council of Lithuania. Ukrainian-Lithuanian project NMR and Vibrational Spectroscopy of Molecular and Ionic Nano-clusters in Aqueous Solutions of Lyotropic Liquid Crystals (financed by project number TAP-LU-15-017). Prof. V. Balevicius.

Achievements: Structural studies of molecular and ionic nano-clusters in aqueous solutions of lyotropic liquid crystals were performed by means of NMR, Raman, and infrared spectroscopy.

Main publication:

Pogorelov, V., Doroshenko, I., Pitsevich, G., Balevičius, V., Šablinskas, V., Krivenko, B., Pettersson, L. 2017. From clusters to condensed phase - FT IR studies of water. Journal of Molecular Liquids, vol. 235, p. 7–10.

Contractual Research 

Service agreement. Measurements of Transmission and Optical Phase Contrast of Optical Phase Retarders in MIR Region. (Nr. APS-120000-43). Prof. V. Šablinskas.  2016–2019.

Service agreement. Measurements of Transmission and Reflection of Optical Crystals in VIS NIR and MIR Regions. (Nr. APS-120000-108). J. Čeponkus. 2016–2019.

MAIN R&D&I (RESEARCH, DEVELOPMENT AND INNOVATION) PARTNERS

Institute of Physics (National Centre of Physical and Technological Sciences) (Lithuania)
Technical University of Darmstadt (Germany)
Technical University of Dresden (Germany)
Paris Sud 11 University (France)
Institute of Bioorganic Chemistry of Polish Academy of Sciences, Poznan (Poland)
National Institute of Chemistry (Slovenia)
Copenhagen University (Denmark)
Stockholm University (Sweden)
Lund University (Sweden)
University of Bialystok (Poland)
Kiev University (Ukraine)
Belarus State University (Republic of Belarus)

OTHER SCIENTIFIC ACTIVITIES

Prof. V. Šablinskas –

• member of Doctoral Committee for Physics at Vilnius University;
• member of Council of the Faculty of Physics;
• chairman of graduate studies committee Applied Physics at Vilnius University.

Prof. V. Balevičius –

• international advisory board member of the Horizons in Hydrogen Bond Research;
• international advisory board member of the Nuclear Magnetic Resonance in Condensed Matter;
• advisory committee member of the International School-Seminar of Galyna Puchkovska on Spectroscopy of Molecules and Crystals.

Dr. V. Urbonienė –

• Institutional ERASMUS coordinator for Physics.

 

DIVISION OF SOLID STATE ELECTRONICS

Tel. 223 4544

E-mail:

Head – Prof. Dr. Kęstutis Arlauskas

STAFF

Professors: Dr. K. Arlauskas, Habil. Dr. G. Juška, Dr. V. Karpus (part-time).
Associate professors:  Dr. A. Poškus, Dr. M.Viliūnas, Dr. V. Jankauskas (part-time), Dr. R. Maldžius (part-time).
Senior research fellows: Dr. K. Genevičius, Dr. N. Nekrašas, Dr. R. Rinkūnas, Dr. G. Sliaužys. Dr. L. Tumonis, Dr. V. Jankauskas (part-time), Dr. R. Maldžius (part-time).
Junior research fellow: R. Dobužinskas, T. Grigaitis, E. Kamarauskas, Dr. B. Lenkevičiūtė-Vasilaisukienė, J. Važgėla.
Doctoral students: A. Aukštuolis, R. Dobužinskas, T. Grigaitis, E. Kamarauskas, J. Nekrasovas, V. Sabonis, M. Stephen, J. Važgėla.

RESEARCH INTERESTS

New Functional Materials and Structures: deposition technologies of new organic, inorganic and hybrid material layers and structures, and investigation of electric, photoelectric and charge carrier transport features

RESEARCH PROJECTS CARRIED OUT IN 2017

Project Supported by University Budget

Solid State Physics and Technologies. Prof. K. Arlauskas.

The method of injected charge extraction by linearly increasing voltage (i-CELIV), which allows independently investigate mobility of both electrons and holes, has been proposed. The CELIV method for the case of dispersive transpot of charge carriers has been developed. Using these methods the charge carrier transport features of various compositions organic solar cells and various morphology lead oxide layers have been investigated.

Main publications:

Semeniuk, O., Grynko, O., Decrescenzo, D., Wang, K., Juska, G., Reznik, A. 2017. Characterization of polycrystalline lead oxide for application in direct conversion X-ray detectors. Scientific Reports, vol.7, p. 8659.

Semeniuk, O., Grynko, O., Juska, G., Reznik, A. 2017. Amorphous lead oxide (a-PbO): suppression of signal lag via engineering of the layer structure. Scientific Reports, vol.7, p. 13272.

A spray method has been applied to form layers of a large area films of titanium oxide and of organic and inorganic materials. For this purpose, a sprayed small area solar cell (SC) were examined and compared to the solar cell layers of the same materials deposited using spin-coating method.

An automatic spray system was developed which can deposit area up to 180 x 180 mm² and adjust the flow of sprayed solution to an accuracy of 1 μl / s.

Using the method of blocking contact layer, we had to investigate the characteristics of carrier transfer and photoionization in new low-ionization energy organic materials for SC. The latter studies were made on adsorbed titanium oxide and perovskite layers. The following groups of organic compounds have been investigated:

1. A series of the fluorene derivatives of hole transport materials with strategically placed aliphatic substituents with the purpose to investigate the relationship between the chemical structure of the HTM’s, photoelectrical properties and the photovoltaic performance. Methyl group in the meta- position prevents tight packing of the molecules.
2. The Fluorenylidene thioxanthene-containing aromatic compounds have been investigated and the optimal content has been found, with the highest holes mobility and maximal SE efficiency.
3. A simple carbazole-based conjugated enamine was synthesized, fully characterized and incorporated into a perovskite solar cell, which displayed high power conversion efficiency (close to 18%).

Main publications:

Rakstys, K., Paek, S., Grancini, G., Gao, P., Jankauskas, V., Asiri, A.M., Nazeeruddin, M.K. 2017. Low-cost perovskite solar cells employing dimethoxydiphenylamine-substituted bistricyclic aromatic enes as hole transport materials. ChemSusChem., vol. 10, Iss. 19, Special Iss. SI, p. 3825–3832, Oct 9 2017; doi: 10.1002/cssc.201700974.

Rakstys, K., Paek, S., Gao, P., Gratia, P., Marszalek, T., Grancini, G., Cho, K.T., Genevicius, K., Jankauskas, V., Pisula, W., Nazeeruddin, M. K. 2017. Molecular engineering of face-on oriented dopant-free hole transporting material for perovskite solar cells with 19% PCE. Journal of Materials Chemistry A, vol. 5, Iss. 17, p. 7811–7815, May 7 2017; doi: 10.1039/c7ta01718a.

Tiazkis, R., Paek, S., Daskeviciene, M., Malinauskas, T., Saliba, M., Nekrasovas, J., Jankauskas, V., Ahmad, S., Getautis, V., Nazeeruddin, M. K. 2017. Methoxydiphenylamine-substituted fluorene derivatives as hole transporting materials: role of molecular interaction on device photovoltaic performance. Scientific Reports, vol. 7, Article nr. 150, p.1–9, Mar 10 2017; doi: 10.1038/s41598-017-00271-z.

Daskeviciene, M., Paek, S., Wang, Z. P., Malinauskas, T., Jokubauskaite, G., Rakstys, K., Cho, K. T., Magomedov, A., Jankauskas, V., Ahmad, S., Snaith, H. J., Getautis, V., Nazeeruddin, M. K. 2017. Carbazole-based enamine: low-cost and efficient hole transporting material for perovskite solar cells. Nano Energy, vol. 32, p. 551–557, Feb 2017; doi: 10.1016/j.nanoen.2017.01.015. 

The effects of the surface composition (barrier coating) on response to the direct current corona treatment were evaluated by measuring contact angles and determining the surface energy. The corona treatment lowered the surface energy of the coatings, as indicated by an increase in the contact angles of water and rapeseed oil. X-ray photoelectron spectroscopy (XPS) tests revealed an increase in the proportion of talc at the surface after corona treatment, which indicates a migration caused by the applied electric field. The peak force tapping mode of an atomic force microscope revealed moderate topographical changes in the coatings and a decrease in surface elasticity, supporting the migration of talc particles.

One of the problems is determination of the ions mobility and their concentration the complex paper structure. These parameters can be calculated from the dielectric spectra and in our work we use the method of paper charge decay kinetics. Mobility of ions is calculated using charge carriers drift model.

Main publications:

Ovaska, S.-S., Geydt, P., Ringaudas, R., Lozovski, T., Maldzius, R., Sidaravicius, J., Österberg, M., Johansson, L. S., Backfolk, K. 2017. Corona treatment of filled dual-polymer dispersion coatings: surface properties and grease resistance. Polymer & Polymer Composites, vol. 25.4, p. 257. http://www.polymerjournals.com/journals.asp?Page=111&JournalType=ppc&JournalIssue=ppc25-4&JIP=

Maldžius, R., Lozovski, T., Sidaravičius, J., Backfolk, K. Jonų judrio ir tankio skaičiavimas popieriuje pagal potencialo išelektrėjimo kinetikas (Calculation of ion mobility and density on paper according to the kinetics of potential discharge). 42-oji Lietuvos nacionalinė fizikos konferencija, October 4-6, 2017, Vilnius. Programa ir pranešimų tezės: Vilniaus universitetas, 2017. p. 111; doi: 10.15388/proceedings/LNFK.42.

The possibility of using the managed photo effect to obtain sapphire and gallium arsenide diffraction spectra, which may allow to obtain practically managed photo effect was explored. X-ray irradiation on CuSO4, NaCl and KCl salt crystals was investigated and it has been noticed that X-rays stimulate the formation of crystals and their growth (sometimes up to 1000 times). The changes in Si monocrystal under X-rays irradiation, as well as in Si covered by carbon films were also studied.

Development of the set of Fortran-90 codes BREMS with the aim of creating a comprehensive library of spectra and angular distributions of unpolarized atomic-field bremsstrahlung for all chemical elements and for the approximate range of the incident electron kinetic energy from 10 eV to 3 MeV on a dense energy grid, using the best theory available. The codes and their detailed descriptions are available at http://web.vu.lt/ff/a.poskus/brems/.

A new version of MCNelectron - an open-source Monte Carlo code for simulation of interaction of high-energy electrons and photons with matter - has been developed and made available for download from http://web.vu.lt/ff/a.poskus/mcnelectron/.

Projects supported by the Research Council of Lithuania

Reseach Council of Lithuania. Study of the Energy Levels and Charge Transfer Parameters of New Bipolar Organic Materials. Dr. V. Jankauskas. 2015–2018. 

Reseach Council of Lithuania. Investigation of the Charge Carriers Transport Features in Thin Multilayered Hybrid Structures. Dr. K. Genevičius. 2015–2018.

Contractual Research 

Research Cooperation Contract: Omega. Coordinators: Stora Enso Oyj, Finland, Vilnius University, Lithuania. Prof. K. Arlauskas. 2017.

MAIN R&D&I (RESEARCH, DEVELOPMENT AND INNOVATION) PARTNERS

Kaunas University of Technology, Kaunas (Lithuania)
Lappeenranta University, Lappeenranta (Finland)
Stora Enso Oyj (Finland)
School of Chemistry and Molecular Biosciences, University of Queensland (Australia)
Thunder Bay Research Institute, Thunder Bay (Canada)

OTHER SCIENTIFIC ACTIVITIES

Habil. Dr. G. Juška –

• editorial board member of the Lithuanian Journal of Physics.
  

 

INSTITUTE OF PHOTONICS AND NANOTECHNOLOGY

3 Saulėtekio, LT-10257 Vilnius
Tel. 223 4482
E-mail: 

Head – Prof. Dr. Saulius Antanas Juršėnas

STAFF

Professors: Dr.  E. Gaubas (part-time), Dr. K. Jarašiūnas (Professor Emeritus), Dr. S. A. Juršėnas (part-time), Dr. V. Kažukauskas, Dr. E. Kuokštis, Dr. V. Tamošiūnas, Dr. G. Tamulaitis (part-time), Dr. R. Tomašiūnas (part-time), Dr. J. V. Vaitkus (Professor Emeritus), Dr. G. Valušis (part-time).
Associate professors: Dr. R. Aleksiejūnas (part-time), Dr. R. Butkutė (part-time), Dr. T. Malinauskas (part-time), Dr. S. Nargelas (part-time), Dr. S. Tamošiūnas (part-time), Dr. P. Vitta (part-time), Dr. E. Žąsinas (part-time).
Assistants: Dr. P. Adomėnas, Dr. A. Arlauskas (part-time), Dr. T. Čeponis (part-time), Dr. J. Jurkevičius (part-time), Dr. I. Kašalynas (part-time), Dr. A. Mekys (part-time), Dr. L. Minkevičius (part-time).
Senior research fellows: Dr. R. Aleksiejūnas, Dr. T. Čeponis, Dr. E. Gaubas, Dr. V. Grivickas, Dr.  S. A. Juršėnas, Dr. A. Kadys, Dr. K. Kazlauskas, Dr. V. Kažukauskas (part-time), Dr. Ž. Lukšienė, Dr. T. Malinauskas, Dr. J. Mickevičius, Dr. G. Tamulaitis, Dr. R. Tomašiūnas, Dr. A. Vaitkuvienė (part-time), Dr. P. Vitta.
Research fellows: Dr. O. Adomėnienė, Dr. V. Bikbajevas, Dr. D. Dobrovolskas, Dr. T. Grinys, Dr. J. Jurkevičius, Dr. A. Mekys, Dr. A. Miasojedovas (part-time), Dr. S. Miasojedovas, Dr. A. Novičkovas, Dr. J. Pavlov, Dr. S. Raišys, Dr. I. Reklaitis, Dr. V. Rumbauskas, Dr. T. Serevičius, Dr. P. Ščajev, Dr. E. Žąsinas.
Junior research fellows: K. Aponienė, I. Buchovec, S. Butkus (part-time), M. Dmukauskas, R. Komskis, K. Gediminas, S. Mačiulytė (part-time), D. Meškauskaitė, K. Nomeika, A. Petrulis, Ž. Podlipskas, A. Zabiliūtė-Karaliūnė.
Engineers: P. Baronas, S. Bikantienė, O. Bobrovas, V. Dadurkevičius, V. Gaidelis, V. Gėgžna, K. Gelžinytė, J. Jovaišaitė, V. Kalcas, K. Kaliatka, L. Kaziukonytė, M. Kolenda, Ž. Komičius, O. Kravcov, G. Medeišienė, S. Nargelas (part-time), P. Herkus, F. Ralienė, D. A. Ralys, V. Ruibys, Dr. A. Samuilis, R. Skaisgiris, J. Vaičiulis, A. Vaitkevičius, D. Varanius.
Technicians: L. Deveikis, R. Lebionka, V. Marčiulionytė, M. Pikaikinas, M. Riauka, K. Pūkas, Ž. Vosylius, V. Žvinytė.
Doctoral students: M. Černauskas, M. Dmukauskas, K. Gelžinytė, M. Kolenda, R. Komskis, O. Kravcov, G. Kreiza, D. Meškauskaitė, K. Nomeika, A. Petrulis, Ž. Podlipskas, S. Raišys, M. Skapas, A. Vaitkevičius, A. Zabiliūtė-Karaliūnė.

RESEARCH INTERESTS

A working out new methods of synthesis of selected structure of organic compounds
Applications of light emitting diodes
Artificial intelligence in various Lithuanian language computer implementations: e.g. machine translation, search systems, intelligent dictionaries, text parsing and data mining
Bio-, immuno-, DNA- sensors based on nanostructured conducting polymers
Carrier transport phenomena in organic materials and solar cell structures
Characterization, optimization and applications of light-emitting diodes and their systems
Computer simulation of crystal surface and defects
Development of GaN devices (LED, detectors, resonators, photonic devices)
Development of laser-based spectroscopic techniques with temporal, spectral, and spatial resolution for characterization of novel semiconductor materials for optoelectronics Development of measurement techniques for comprehensive characterization of photo-sensors, particle detectors, light emitting diodes and solar-cells
Development of measurement technologies and instrumentation for the in situ characterization of material and device structures under heavy irradiations by hadrons
Development of novel glass ceramic materials for optoelectronic applications
Development of novel organic materials and technologies for optoelectronic applications
Development of the dictionary of contemporary Lithuanian
Development of ultrafast scintillation detectors and infrared radiation-hard detectors
Dosimetry of large fluence irradiations
Dynamics of nonequilibrium carriers and excitons in highly excited semiconductors and their low-dimensional structures
Efficient technology for ultra-pure liquid crystal and OLED intermediates
Epitaxy of GaN and alloys, multi-quantum wells by MOCVD technology
Formation of OLED, light upconversion structures and organic sensor systems
Intelligent solid-state lighting systems for outdoor lighting
Investigation of native and ionizing radiation induced defects and micro-inhomogeneities in semiconductor materials and device structures
Investigation of photoinduced phenomena and optical memory effect in trinomial chalcogenide layers
Lighting systems for vegetable growth with improved nutritional quality
Lighting systems with advanced colour rendition control for general and niche lighting
New compounds and intermediates for OLED technology
Nondestructive characterization of wide band gap semiconductor materials
Nonequilibrium carrier relaxation, transport and related photoelectrical phenomena in highly excited semiconductors and their nanostructures
Optical nonlinearities in semiconductors caused by free carriers, electrooptic and spin-related mechanisms
Organic material (alanine) based dosimetry
Photophysics of organic electronics compounds
Radiation detectors, high-density scintillation crystals
Spectroscopic characterization of novel inorganic and organic semiconductor materials for optoelectronics
Spectroscopy of deep levels in wide-gap semiconductors as GaN and different technology diamond
Structural, optical and electrical properties of InGaN/GaN multi-quantum wells
Structure and photoluminescence spectroscopy investigation of polar, semi-polar and non-polar III-nitride structures
Synthesis methods for nitrogen and sulphur heterocycles, highly branched aromatic compounds
Synthesis of organic compounds by methods known from the literature
Trans-cis mobility in polymers, also at the GaN surface
Wide –gap material scintillators for detection and dosimetry of hadron irradiations

RESEARCH PROJECTS CARRIED OUT IN 2017

Projects Supported by University Budget

Creation, Research and Application in Optoelectronics of the Promising Semiconductor Structures /Investigations in Semiconductor Material Science and Development of Specific Research Techniques. Prof. Habil. Dr. E. Gaubas. 2017.

Project addresses the development of measurement techniques by combining the electrical and spectral characteristics of wide–gap semiconducting materials such as GaN, and synthetic diamond. The pulsed photo-ionization spectroscopy technique using microwave probes combined with spectroscopy of carrier recombination and trapping centres using microwave probed photoconductivity transients have been developed for inspection of deep levels ascribed to technological and radiation induced defects in wide-gap semiconductors. The in situ and ex-situ variations of the radiation induced photo-ionization, of barrier and storage capacitance recorded by pulsed capacitance technique and time-resolved luminescence spectra have been examined. The profiling techniques for analysis of the current transients in junction and capacitor type detectors have been developed, and these techniques were applied for evaluation of the operation performance of photo- and particle sensors. Parameters of detectors, such as transit time, diffusion time and polarization recovery time have been extracted for sensors of various configurations. The origin of the prevailing radiation defects in GaN materials of different technology have been revealed by combining ESR, absorption, Raman scattering and luminescence spectroscopy techniques.

Main publication:

Gaubas, E., Ceponis, T., Deveikis, L., Meskauskaite, D., Miasojedovas, S., Mickevicius, J., Pavlov, J., Pukas, K., Vaitkus, J., Velicka, M., Zajac, M., Kucharski, R. 2017. Study of neutron irradiated structures of ammonothermal GaN, J. Phys. D: Appl. Phys., vol. 50, p. 135102.

                     
Development of Technologies for High Energy Radiation Detectors and Means for Passivation of Radiation Deffects. Prof. Habil. Dr. E. Gaubas. 2017.

Project is focussed on designing the specific detection regimes by combining the electrical and scintillation response in detectors made of wide–gap semiconducting materials such as GaN, CdS, and synthetic diamond. Tentative detectors of various configurations have been designed and fabricated. The pulsed photo-ionization spectroscopy and combined with spectroscopy of carrier recombination and trapping centres using microwave probed photoconductivity transients have been applied for inspection of deep levels ascribed to technological and radiation induced defects in wide-gap semiconductors. Parameters of detectors, such as transit time, diffusion time and polarization recovery time have been extracted for sensors of various configurations. The spectra of the thermal- and photo-ionization of traps have been examined in GaN and diamond structures by combining the pulsed photo-ionization, DLTS and time-resolved photoluminescence spectroscopy techniques. The role of radiation defect clusters and point complexes, aggregated through large density of radiation induced vacancy and interstitial defects, was also considered by the comprehensive study of recombination characteristics within FZ and MCz Si structures irradiated with high energy electrons, pions and protons. Formation of deep levels attributed to multi-vacancy structures in Si and GaN have been modelled. Tentative investigations of DLTS spectra with spectral peaks ascribed to radiation clusters have been performed. These results were correlated with pulsed photo-ionization spectra and with variations of the temperature dependent carrier trapping lifetime in the same materials and samples. The ESR spectra ascribed to clusters of radiation defects have also been examined in heavily irradiated Si. The possible ways for passivation of radiation defects using heat treatments at elevated temperatures were researched and the most promising passivation regimes have been determined.

Main publications:

Gaubas, E., Ceponis, T., Meskauskas, D., Pavlov, J., Zukauskas, A., Kovalevskij, V., Remeikis, V. 2017. In situ characterization of radiation sensors based on GaN LED structure by pulsed capacitance technique and luminescence spectroscopy. Sens. & Act., vol. A 267, p. 194–199.

Development, Investigation and Application of Advanced Semiconductor Structures for Optoelectronics. Dr. R. Tomašiūnas. 2016–2018.

Growth of gallium nitride structures by using MOCVD technology has been continued. In the period most of efforts were made to grow the p-type GaN/InN junction structure. By means of SEM, EBIC and I-V measurement techniques the junction has been investigated and optimized. Investigation of photo induced phenomena and optical memory effect in trinomial chalcogenide layers has been continued. Investigation of chalcogenides and silicon carbide using optical and electronic methods for potential applications for photonic devices and switches.

Development of General Language Resources and Technologies. Dr. A. Samuilis.

Social texts accessible on the Internet were analyzed and elements of non-standard vocabulary were selected; elements of non-standard lexis were selected from publicly available press publications (books, dictionaries, newspapers and magazines); the morphological classification of selected non-lexical lexical elements was performed.

Organic Optoelectronics. Prof. Habil. Dr. S. A. Juršėnas. 2016–2017.

Efficient synthesis and purification routes of organic electronic compounds were developed. Photophysical properties of functional organic films were elucidated and optimized for realization of high-performance optoelectronic devices such as 3^rd generation OLEDs, sensors etc. Fabrication technology of superior quality organic single crystals by physical vapor transport for lasing applications was developed. Technologies for solution processing of organic materials in inert atmosphere as well as their evaporation in vacuum were acquired. Electron and atomic force microscopies were employed for investigation of surface topography/morphology of organic films. Ultrafast transient absorption spectroscopy was applied for evaluation of excited state dynamics in organic electronic compounds.

Main publications:

Matulaitis, T., Imbrasas, P., Kukhta, N. A., Baronas, P., Bučiu̅nas, T., Banevičius, D., Kazlauskas, K., Gražulevičius, J. V., Juršėnas, S. 2017. Impact of donor substitution pattern on the TADF properties in the carbazolyl-substituted triazine derivatives. J. Phys. Chem. C, vol. 121, p. 23618–23625.

Ivanauskaite, A., Lygaitis, R., Raisys, S., Kazlauskas, K., Kreiza, G., Volyniuk, D., Gudeika, D., Jursenas, S., Grazulevicius, J. V. 2017. Structure–property relationship of blue solid state emissive phenanthroimidazole derivatives. Phys. Chem. Chem. Phys., vol. 19, p. 16737–16748.

Aponiene, K., Serevičius, T., Luksiene, Z., Juršėnas, S. 2017. Inactivation of bacterial biofilms using visible-light-activated unmodified ZnO nanorods. Nanotechnology, vol. 28, p. 365701.

Braukyla, T., Sakai, N., Daskeviciene, M., Jankauskas, V., Kamarauskas, E., Regimantas K., Malinauskas, T., Jursenas, S., Snaith, H. J., Getautis V. 2017. V-shaped hole-transporting TPD dimers containing Tröger’s base core. J. Phys. Chem. C, vol. 121, p. 10267–10274.

Solid-State Lighting Technologies. Dr. P. Vitta. 2016–2018.

A novel method for evaluation of recombination coefficients corresponding to Shockley-Read-Hall, radiative, and Auger recombination channels has been proposed, which combines measurements of the light emitting diode (LED) external quantum efficiency under continuous wave operation with the determination of non-equilibrium carrier differential life time (DLT) by small-signal time-resolved photoluminescence. Therefore, an alternative technique, small-signal frequency-domain lifetime measurements was suggested with a potential to implement more easily and capable of operating in a wider range of LED operating currents. The DLTs measured by both techniques were shown to agree well with each other, but saturate at low currents, contrary to the trend predicted by the well-known ABC-model. Possible reasons for this deviation, as well as advantages and limitations of the measurement techniques are discussed.

The existence of regions of correlated color temperature (CCT) and illuminance at which the illumination is considered “pleasing” (Kruithof hypothesis) has been tested in several outdoor environments using a smart tetrachromatic solid-state light engine with tunable CCT and high-fidelity color rendition. Subjects from a culturally homogeneous group were asked to find the most “pleasing” illumination conditions at the set illuminance levels of 5 lx and 50 lx by performing a CCT adjustment task within a wide range of 1850–10,000 K at a fixed initial condition of 1900 K. The selected intervals or preferred CCT were found to shift to higher values with increased illuminance almost independently of the content of the viewed scene with statistical significance, which qualitatively is in agreement with the Kruithof hypothesis. However, the intervals of CCT for pleasing illumination were found to be shifted to a broader and higher “warm white” range than those predicted by Kruithof. In addition, subjects were asked to find the most pleasing illumination conditions when the adjustment of CCT was accompanied by instantaneous dimming in order to maintain constant circadian irradiance.

Main publications:

Reklaitis, F., Nippert, R., Kudzma, T., Malinauskas, S., Karpov, I., Pietzonka, H. J., Lugauer, M., Strassburg, P., Vitta, R., Tomasiunas, A., Hoffmann. 2017. Differential carrier lifetime in InGaN-based light-emitting diodes obtained by small-signal frequency-domain measurements. J Appl. Phys., vol. 121 (3), art. No. 035701.

Petrulis, A., Petkevičius, L., Vitta, P., Vaicekauskas, R., Žukauskas, A. 2017. Exploring preferred correlated color temperature in outdoor environments using a smart solid-state light engine. Leukos; doi: 10.1080/15502724.2017.1377085.  

National Research Projects

Research Council of Lithuania. Scientist initiative project: Colour Restoration in Cultural Heritage Objects Using Solid-State Lighting. Dr. R. Vaicekauskas of the Faculty of Mathematics and Informatics. 2015–2017.

The objects of cultural heritage, such as paintings, textiles, and jewellery, are damaged by the environmental factors over the time. The restoration of these objects, which aims at revealing the original visual appearance, is highly resource demanding task that is often associated with destructive physical impact. The idea of the Project HeriLED is to investigate the possibility of recreating the original appearance of an damaged object using a lighting device having appropriate spectral power distribution that is comprised of light-emitting diodes (LEDs), when the assumed original visual appearance is available from an undamaged fragment (e.g. back side of the tapestry).

Research Council of Lithuania. Researcher teams’ project: Control of Nitrate Reduction in Green Vegetables: Metabolic Effects of Light and other Environmental Factors. Dr. A. Viršilė of the Institute of Horticulture of Lithuanian Research Centre for Agriculture and Forestry, and Vilnius University. 2015–2018.

Nitrate level in plants depends on lighting conditions, particularly on the light flux density. Light affects nitrate metabolism directly and through photosynthesis biochemical signals. The aim of this project is to evaluate photophysiological effects on nitrate assimilation processes in green vegetables and to prepare the model, based on biochemical assays, for the control of nitrate reduction and related metabolic processes by light and other environmental factors. 

This is of particular importance in greenhouse conditions, where plants are affected by labile environmental factors, including both natural and artificial light. For supplemental lighting were developed solid-state lamps with light-emitting diodes (LEDs) generating extra high photosynthetic photon flux (up to 1/2 of Sun).

Research Council of Lithuania. Development of Nonpolar GaN on Silicon Growth Technology with Rare-Oxide Interlayers (NEAPOLIS) (No. MIP-15283). Dr. T. Malinauskas. 2015–2017.

The non-polar, semi-polar crystalline GaN growth technology on silicon with rare-oxide interlayer was developed. Monocrystalline semi-polar truncated pyramids and polycrystalline GaN layers with dominating non-polar and semi-polar orientation were grown by MOCVD technique using different growth conditions such as carrier gas, temperature, interlayers etc. The layers were investigated by XRD, PL and optical transmittance/reflectance techniques. Using XRD pole figure measurements the growth mechanism of nonpolar and semipolar GaN on ErO was revealed. It was shown that GaN tends to grow on (111) planes of ErO, thus causing crystal twinning and surface roughening. These experiments also revealed how in-plane orientation of ErO influences the growth of semipolar (10-13) phase of GaN.

Main publication:

Grinys, T., Drunga, T., Badokas, K., Dargis, R., Clark, A., Malinauskas, T. 2017. Growth conditions of semi and non-polar GaN on Si with Er2O3 buffer layer. J. Alloys Compd., vol. 725, p. 739.

Research Council of Lithuania. Distinction of the Influences of Defects and Carrier Localization on Emission in Green InGaN LED Structures (Delokingan) (No. MIP-079/2015). Dr. J. Mickevičius. 2015–2018.

The project is focused on technological study of growth of InGaN structures emitting in a wide spectral range using MOCVD and optimization of growth parameters, investigations of spatial distribution of luminescence in InGaN epilayers and quantum well structures, and study of the relation between carrier dynamics and localization in InGaN structures.

Main publications:

Mickevičius, J., Dobrovolskas, D., Aleksiejūnas, R., Nomeika, K., Grinys, T., Kadys, A., Tamulaitis, G. 2017. Influence of growth temperature on carrier localization in InGaN/GaN MQWs with strongly redshifted emission band. Journal of Crystal Growth, vol. 459, p. 173; doi:10.1016/j.jcrysgro.2016.12.008.

Dobrovolskas, D., Mickevičius, J., Nargelas, S., Vaitkevičius, A., Nanishi, Y., Araki, T., Tamulaitis, G. 2017. Influence of defects and indium distribution on emission properties of thick In-rich InGaN layers grown by the DERI technique. Semiconductor Science and Technology, vol. 32, p. 025012; doi: 10.1088/1361-6641/32/2/025012.

Research Council of Lithuania. Enhancing Light Upconversion Efficiency in Organic Films for Optoelectronic Applications (Lightupcon) (No. S-MIP-17-77). Dr. K. Kazlauskas. 2017–2020.

The project is focussed on improving light upconversion efficiency in organic solid films via triplet‐triplet annihilation (TTA) for optoelectronic applications. TTA allows accomplishing light upconversion (UC) in organic films from longer wavelengths to shorter ones by irradiating them with low intensity non‐coherent light, e.g. sunlight. The application of TTA‐UC films opens up possibilities to enhance efficiency of solar cells by means of converting of poorly absorbed red‐IR photons to shorter wavelength photons, which can contribute to photocurrent. One of the unresolved problems of TTA‐UC – very low UC efficiency in organic films (1 ‑ 2%), what hinders their practical applications. The project will focus on identification and elimination of the factors limiting TTA‐UC efficiency in organic solid films.

European TD COST Action TD1401: Fast Advanced Scintillator Timing (FAST).  Prof. Habil. Dr. G. Tamulaitis. 2014–2018.

FAST aims at establishing an interdisciplinary network that brings together experts from different fields of interest in order to develop photon instrumentation with an unparalleled timing precision of < 100ps.

European COST Action MP1302: NanoSpectroscopy. Prof. Habil. Dr. G. Tamulaitis. 2013–2017.

The COST Action NanoSpectroscopy aims at gathering European expertise in order to further develop UV/Vis/NIR/Raman nanospectroscopic techniques and modeling with (ultra-)high spatial, temporal, and spectral resolution and sensitivity, and the application of these techniques to novel (hybrid) (in)organic nanomaterials, complex device structures, and biosystems.

Research Council of Lithuania. Origins and Pathways of Non-Radiative Recombination in Nonpolar and Semipolar Ingan Structures (NORAD) (No. MIP-17-75). Dr. S. Nargelas. 2017–2020.

The project aims at investigations of recombination pathways of free carriers in III-nitride structures oriented along the non-polar and semi-polar axis. In this project, a novel method of sample growth will be implemented, where InGaN structures will be deposited by pulsed-MOCVD on native GaN substrates.

Research Council of Lithuania. Perovskite Laser (PERLAS) (No. MIP-17-71). Prof. S. Juršėnas. 2017–2020.

In this project, the technology of a perovskite laser emitting in the visible range will be developed. Unique investigation techniques and sophisticated deposition technologies will be applied to optimize the carrier transport and optical parameters of the perovskite layers, seeking to achieve very low threshold of amplified spontaneous emission and lasing.

Main publication:

Ščajev, P., Aleksiejūnas, R., Miasojedovas, S., Nargelas, S., Inoue, M., Qin, C., Matsushima, T., Adachi, C., Juršėnas, S. 2017. Two regimes of carrier diffusion in vapor-deposited lead-halide perovskites. Journal of Physical Chemistry C, vol. 121, p. 21600; doi: 10.1021/acs.jpcc.7b04179.

Projects Supported by the Lithuanian Academy of Science

Project: Scintillators for Future Calorimeters (No. CERN-VU-2016-1).  Prof. Habil. Dr. G. Tamulaitis. 2017.

Project is devoted to research into new inorganic scintillation materials for novel ionizing radiation detectors for high-energy physics, medical imaging and industrial applications.

Main publications:

Tamulaitis, G., Vaitkevičius, A., Nargelas, S., Augulis, R., Gulbinas, V., Bohacek, P., Nikl, M., Borisevich, A., Fedorov, A., Korjik, M., Auffray, E. 2017. Subpicosecond luminescence rise time in magnesium codoped GAGG:Ce scintillator. Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 870, p. 25–29; doi: 10.1016/j.nima.2017.07.015.

Korjik, M., Alenkov, V., Borisevich, A., Buzanov, O., Dormenev, V., Dosovitskiy, G., Dosovitskiy, A., Fedorov, A., Kozlov, D., Mechinsky, V., Novotny, R.W., Tamulaitis, G., Vasiliev, V., Zaunick, H.-G., Vaitkevičius, A. 2017. Significant improvement of GAGG:Ce based scintillation detector performance with temperature decrease. Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 871, p. 42–46; doi: 10.1016/j.nima.2017.07.04.

Lucchini, M. T., Buganov, O., Auffray, E., Bohacek, P., Korjik, M., Kozlov, D., Nargelas, S., Nikl, M., Tikhomirov, S., Tamulaitis, G., Vaitkevicius, A., Kamada, K., Yoshikawa, A. 2018. Measurement of non-equilibrium carriers dynamics in Ce-doped YAG, LuAG and GAGG crystals with and without Mg-codoping. Journal of Luminescence, vol. 194, p. 1–7.

National Research Programme Towards Future Technologies: III-nitride Semiconductors for Radiation-Hard Infrared Detectors (Irdet) (No. LAT-05/2016). Prof. Habil. Dr. G. Tamulaitis. 2016–2018.

The project is aimed at optimization of growth conditions for InN and low-Ga-content InGaN epitaxial layers and heterostructures to meet the requirements for utilization in infrared detectors and to ensure the radiation hardness, which is sufficient for exploitation in space applications.

International Research Projects

H2020 Project AIDA-2: Advanced European Infrastructures for Detectors at Accelerators. Prof. Habil. Dr. J.V.Vaitkus, Prof. Habil. Dr. G. Tamulaitis. 2015–2018.

VU WP (at the Department of New Materials Research and Measurement Technology). The Project is devoted to search and investigations of the simple and cheap technology Si wafers for fabrication of dosimeters exploited in dose-reading using VUTEG-5-AIDA instrument.

M-ERA.NET. Functional Inorganic Layers for Next Generation Optical Devices (FLINGO). Dr. R. Tomašiūnas. 2016–2019.

During the first months of implementation of the project kick-off meeting was visited. Project website was discussed with partners and preparations started. Among partners suitable experimental set-ups need for project implementation were discussed and selected.

Lithuanian–Belarus research project. Transient Optical Processes in Compensated Silicon Carbide and Chalcogenide 2D Semiconductors (LB-17-001). Dr. V. Grivickas 2017–2018.

Main publication:

Korolik, O.V., Kaabi, S.A.D., Gulbinas, K., Mazanik, N.V., Drozdov, N.A. 2017. Band edge photoluminescence of undoped and doped TlInS₂ layered crystals. J. Luminesc., vol. 187, p. 507.

Research Council of Lithuania. Joint Lithuania-Japan research project: Towards Organic Laser Transistor (Laser-OTFT) (No. LJB-3/2015). Prof. Habil. Dr. S. A. Juršėnas. 2015–2017.

In the final stage of the project a new series of bifluorene derivatives possessing rigid molecular bridges were synthesized and thoroughly characterized. One of the compounds from this series expressed amplified spontaneous emission threshold (400 W/cm²) in the sublimation-grown single crystal twice as low as compared to that obtained during the first year. Sophisticated femtosecond pump-probe spectroscopy analysis revealed small amount of traps (of unknown nature) present in the crystal, which were found to be responsible for efficient energy trapping and thereby resulting in the low-threshold light amplification. The research carried out in the framework of current project practically solved the issues related to optical gain media, however, efficient carrier injection still remained a problem, which is expected to be circumvented by utilizing doping technique.

Main publications:

Montinaro, M., Resta, V., Camposeo, A., Moffa, M., Morello, G., Persano, L., Kazlauskas, K., Jursenas, S., Tomkeviciene, A., Grazulevicius, J. V., Pisignano, D. 2017. Diverse regimes of mode intensity correlation in nanofiber random lasers through nanoparticle doping. ACS Photonics, doi: 10.1021/acsphotonics.7b01329.

Resta, V., Camposeo, A., Montinaro, M., Moffa, M., Kazlauskas, K., Jursenas, S., Tomkeviciene, A., Grazulevicius, J. V., Pisignano, D. 2017. Nanoparticle-doped electrospun fiber random lasers with spatially extended light modes. Opt. Express, vol. 25, p. 24604–24614.

Contractual Research

MTEP project. Characterization of Photoconductivity and Relevant Material Properties in Diamond Specimens.  Dr. V. Grivickas. 2017.

MAIN R&D&I (RESEARCH, DEVELOPMENT AND INNOVATION) PARTNERS

Acros Organics B.V.B.A. (Belgium)
Adolphe Merkle Institute, University of Fribourg (Switzerland)
Advinus Therapeutics PVT Ltd. (India)
Aixtron AG (Germany)
Akos Consulting & Solutions GmbH (USA)
Alfa Aesar, Avocado Research Chemicals Ltd. (UK)
Alfa Aesar GmbH & Co. KG (Germany)
Alkali Metals Ltd. (India)
AppliChem GmbH (Germany)
Austin Chemical Company, Inc. (USA)
BCH Research L.L.P. (USA)
BCR GmbH & Co. KG (Germany)
Camida Ltd. (Ireland)
Carl Roth GmbH & Co. (Germany)
Centre of Organic Electronics and Photonics Research, Kyushu University (Japan)
Centre for Physical Sciences and Technology (Lithuania)
Chemosyntha N.V. (Belgium)
Chukan Butsu Ltd. (Japan)
CMS Chemicals Ltd. (UK)
Connect Marketing GmbH (Switzerland)
Crystal Clear Collaboration (RD18) at CERN
Discovery Fine Chemicals Ltd. (UK)
DKSH Switzerland Ltd. (Switzerland)
Durham University (United Kingdom)
Elite Inter-Chem FZC (UnitedArabEmirates)
Eurolabs Ltd. (UK)
Fraunhofer ISC (Germany)
International Centre for Genetic Engineering And Biotechnology (India)
JSC Ledigma (Lithuania)
JSC Tikslioji sintezė (Lithuania)
Kaunas University of Technology (Lithuania)
KISCO Deutschland GmbH (Germany)
KISCO Tokyo Ltd. (Japan)
Korea University (South Korea)
Lawrence Livermore National Laboratory (USA)
Matrix Marketing GmbH (Switzerland)
Maybridge Ltd. (UK)
MBraun Inertgas-Systeme GmbH (Germany)
Military University of Technology (Poland)
Mirae Interchem Co. Ltd. (South Corea)
Molekula UK Ltd. (UK)
MP Biomedicals LLC (USA)
National Institute of Advanced Industrial Science and Technology (AIST) (Japan)
Niche Materials Ltd. (UK)
Organica Feinchemie GmbH Wolfen (Germany)
OSRAM Opto Semiconductors (Germany)
Panslavia Chemicals LLC (USA)
PPW "AWAT" Spolka z o. o (Poland)
Rensselaer Polytechnic Institute (Troy NY, USA)
Royal Institute of Technology (Sweden)
Santa Cruz Biotechnology Inc (USA)
Sensor Electronic Technology Inc. (USA)
Sigma-Aldrich Logistik GmbH (Germany)
Sumitomo Shoji Chemicals Co. Ltd. (Japan)
Synthon Chemicals GmbH & Co.KG (Germany)
Taiwan National University
TCI Europe NV (Belgium)
Tianjin Datao International Trade Co. Ltd. (China)
TOPGAN (Poland)
Translucent Inc. (USA)
UCB Pharma SA (Belgium)
Ukrorgsyntez Ltd. (Ukraine)
University of Alicante (Spain)
University of Bordeaux (France)

OTHER SCIENTIFIC ACTIVITIES

Dr. V. Bikbajevas –

• member of the Lithuanian Material Research Society (LtMRS), http://www.ltmrs.lt/en/membership/;
• member of the Lithuanian Physical Society.

Dr. V. Grivickas –

• vice president of the Lithuanian Materials Research Society (LtMRS), www.ltmrs.lt/members/v_grivickas/.

Prof. S. Juršėnas –

• member of the Lithuanian Material Research Society (LtMRS), http://www.ltmrs.lt/en/membership/.

Prof. G. Tamulaitis –

• member of the Lithuanian Material Research Society (LtMRS), http://www.ltmrs.lt/en/membership/;
• member of the Lithuanian Physical Society;
• member of Lithuanian Academy of Sciences, http://www.lma.lt/members-of-the-academy.

Dr. R. Tomašiūnas –

• member of the Technical Committee 73 Nanotechnologies, Lithuanian Standards Board;
• member of the Lithuanian Material Research Society (LtMRS), http://www.ltmrs.lt/en/membership/;
• member of the management committee of COST MP1403 Nanoscale Quantum Optics action.

 

LASER RESEARCH CENTRE

10 Saulėtekio, LT-10223 Vilnius

Tel: 236 6050;  236 6005

E-mail:

Head - Prof. Habil. Dr. Valdas Sirutkaitis

STAFF

Professors: Habil. Dr. R. Rotomskis, Habil. Dr. V. Sirutkaitis, Habil. Dr. V. Smilgevičius, Dr. A. Dubietis, Dr. G. Valiulis, Dr. S. Bagdonas, Dr. R. Gadonas, Dr. M. Vengris, Habil. Dr. A. Piskarskas (emeritus), Habil. Dr. A. Stabinis (emeritus).
Associate professors: Dr. O. Balachninaitė, Dr. R. Butkus, Dr. A. Čiuplys (part-time), Dr. V. Jarutis, Dr. V. Jukna, Dr. V. Karenauskaitė, Dr. V. Kudriašov, Dr. A. Matijošius, Dr. A. Melninkaitis, Dr. D. Paipulas, Dr. G. Tamošauskas, Dr. V. Tamulienė.
Lecturers: J. Jurkienė, Dr. R. Piskarskas.
Leading researchers: Dr. V. Vaičaitis, Dr. A. Varanavičius.
Senior research fellows: Dr. E. Gaižauskas, Dr. R. Grigonis, Dr. M. Malinauskas.
Research fellows: Dr. D. Kaškelytė, Dr. M. Peckus, Dr. S. Rekštytė, Dr. V. Purlys.
Head of the Teaching Laboratory: A. Čiburys.
Doctoral students: R. Budriūnas, S. Butkus, D. Gailevičius, N. Garejev, P. Grigas, M. Ivanov, L. Jonušauskas, A. Marcinkevičiūtė, L. Mažulė, K. Michailovas, B. Momgaudis, I. Pipinytė, L. Smalakys, S. Sobutas, P. Stanislovaitis, I. Stasevičius, R. Šuminas, T. Tičkūnas, S. Varapnickas, J. Vengelis.

RESEARCH INTERESTS

Study of interaction of high power ultrashort light pulses with transparent media
Development of effective light frequency convertors and light pulse sources with the duration of few optical cycles and stable carrier-envelope phase
Study of femtosecond light filaments and generation of supercontinuum in transparent dielectrics
Development of new technologies for biomedical and industrial applications based on specific interaction of ultrashort light pulses with matter, enabling high precision material processing by surface and bulk modification
Development of optical methods of biomedical diagnostics and extension of application areas
In vivo and in vitro studies of spectral and photophysical properties of biologically active molecules and nanostructures aiming at optimisation of therapy and diagnostics
Imaging and spectroscopy of biologic objects
Nonlinear optics of ultrashort pulses
Ultrafast spectroscopy of photoactive molecules, nanostructures and semiconductors
Laser surgery using femtosecond light pulses
Damage in bulk materials and coatings induced by femtosecond pulses
Optics characterization including reflection/transmission, scattering as well as absorption and laser-induced optical damage threshold in wide spectral range
Peculiarities of ultrafast exciton dynamics at reduced dimension in self-assembled molecular nanostructures and quantum dots
Laser submicro- and nanoscale engineering of functional 3D devices
High intensity ultrashort pulse generation by OPCPA systems
Time-resolved digital holography
Formation of the coherent light by the incoherent pump in the nonlinear crystals
Radial/azimuthal polarization beams, Bessel beams and optical vortices

RESEARCH PROJECTS CARRIED OUT IN 2017

Projects Supported by University Budget

Study of Fundamental Ultrafast Processes in Laser and Nonlinear Optical Systems. Prof. V. Sirutkaitis. 2013–2017.

A high peak and average power optical parametric chirped pulse amplification system driven by diode-pumped Yb:KGW and Nd:YAG lasers running at 1 kHz repetition rate has been developed. The advanced architecture of the system allows us to achieve >53W average power combined with 5.5TW peak power, along with sub-220 mrad CEP stability and sub-9 fs pulse duration at a center wavelength around 880 nm.. Excellent stability of output parameters over 16 hours of continuous operation was demonstrated.

A new technique for photonic crystal fiber dispersion measurement was prposed. It was demonstrated that investigating supercontinuum using cross-correlation frequency resolved optical gating (XFROG) technique can be used for quantitatively characterizing dispersion and observing orthogonal polarization modes in polarization maintaining photonic crystal fibers. In addition, an XFROG trace of supercontinuum generated in a polarization maintaining photonic crystal fiber reveals complex behavior of orthogonal polarization modes that is different in normal and anomalous dispersion regions of the photonic crystal fiber.

Generation of spatially and temporally coherent continua spanning nearly two octaves with spectral energy densities exceeding 10 nJ/nm by pumping an array of thin transparent plates with  hundreds-of-μJ-level 60 fs infrared pulses tunable from 1.2 to 1.75 μm has been demonstrated. Compared to continua produced by filamentation in continuous solid media, the spectral energy density of the multi-plate continuum is higher by two to three orders of magnitude. The continuum pulses exhibit strongly self-compressed features, which could be separated from the rest of the pulse by spectral filtering, allowing direct production of few-cycle pulses.

A method to form radially and azimuthally polarized beams as well as higher order polarization singularities by superposition of optical vortices with opposite topological charges obtained by optical parametric amplification was shown. The proposed method could find applications in optical trapping of particles, nonlinear optics experiments, and laser material processing.

Spectral and spatial properties of infrared femtosecond laser pulses with a wavelength between 1.2 and 1.6 µm propagating in air were investigated both experimentally and theoretically.  It was shown that under tight focusing conditions laser pulses experience asymmetric spectral broadening and a strong blue-shift with respect to the incident laser wavelength. The observed blue-shifted radiation is emitted conically, in contrast to the weaker red-shifted on-axis emission. The spectral broadening and frequency shifts were interpreted in terms of ionization-induced effects.

Main publications:

Budriūnas, R., Stanislauskas, T., Adamonis, J., Aleknavičius, A., Veitas, G., Gadonas, D., Balickas, S., Michailovas, A., Varanavičius, A. 2017. 53 W average power CEP-stabilized OPCPA system delivering 5.5 TW few cycle pulses at 1 kHz repetition rate. Opt. Express, vol. 25, p. 5797–5806.

Vengelis, J., Jarutis, V., Sirutkaitis, V. 2017. Estimation of photonic crystal fiber dispersion by means of supercontinuum generation. Optics Lett., vol. 42, p. 1844–1847.

Budriūnas, R., Kučinskas, D., Varanavičius, A. 2017. High‑energy continuum generation in an array of thin plates pumped by tunable femtosecond IR pulses. Appl. Phys. B, vol. 123; doi:10.1007/s00340-017-6785-9.

Stanislovaitis, P., Ivanov, M., Matijošius, A. Smilgevičius, V., Gertus, T. 2017. Generation of radially polarized beams and higher order polarization singularities by optical parametric amplification of optical vortices. Opt. Engineering, vol. 56, p. 095101–1–095101–8.

Development of Laser Technologies for Industrial and Biomedical Applications. Prof. R. Gadonas. 2013–2017.

Optical readout of local-heating in SZ2080 prepolymer being processed by direct laser writing nanopolymerization technique (1030 nm, 300 fs, 200 kHz, NA=0.8) was carried out. Variation of thermally-coupled spectral bands fluorescence intensity ratio by dispersed nanocrystals was observed in pulse energy range varying from below modification threshold to the optical breakdown. Average fitted temperature changes around polymerized voxel measured ∆T<30°C within polymerization window and increases up to ∆T>100°C in overexposing regime.

Physicochemical properties of golden nanoparticles and synthetized up-converting nanoparticles were studied revealing the sensor properties in the former, and the diagnostic potential of multimodal agents in model biological environments in the latter. The effects of quantum dots on the activity of mesenchymal stem cells were evaluated, and the study of its potential embryotoxicity was performed in cooperation with Nacional Cancer Institute.

Main publications:

 Čiplys, D., Poderys, V., Rotomskis, R., Shur, M. S. 2017. Fast-response and low-loss surface acoustic wave humidity sensor based on bovine serum albumin-gold nanoclusters film. Sensors and Actuators B, vol. 239, p. 352–357.

Matulionyte, M., Dapkute, D., Budenaite, L. Jarockyte, G., Rotomskis, R. 2017. Photoluminescent gold nanoclusters in cancer cells: cellular uptake, toxicity, and generation of reactive oxygen species. International Journal of Molecular Sciences, vol. 18, p. 378.

Dapkute, D., Steponkiene, S., Bulotiene, D., Saulite, L., Riekstina, U., Rotomskis, R. 2017. Skin-derived mesenchymal stem cells as quantum dot vehicles to tumors. International Journal of Nanomedicine, vol. 12, p. 8129–8142. 

National Research Projects

Research Council of Lithuania. Healthy Aging Project: Fabrication of 3D Microstructured and Collagen Scaffolds with Chondrogenic Cells and Translational Application for Cartilage Regeneration (ReGen) (No. SEN-20/2015), Prof. R. Mačiulaitis. 2015–2018.

Scaffolds with different pore shapes (hexagons and rectangles) were fabricated using direct laser writing (DLW) in pre-polymers technique. After seeding them with chondrocytes the influence of pore shape to cell proliferation and production of extracellular matrix was determined. Rectangular pore shape was chosen to further investigate the importance of pore size (scaled by factors 1.5 and 2). Also, mechanical properties of the DLW fabricated scaffolds are being investigated and compared with collagen membranes.

Main publications:

Rekštytė, S., Paipulas, D., Malinauskas, M., Mizeikis, V. 2017. Microactuation and sensing using reversible deformations of laser-written polymeric structures. Nanotechnology, vol. 28(12), p. 124001.

Research Council of Lithuania. Programme towards Future Technologies project: Optical 3D Micro‐/nano‐processing of Bioplastics (OptiBioForm) (No. S-LAT-17-2).

Vilnius University and Kaunas University of Technology, Dr. M. Malinauskas (2017–2018). The goal of this Project is to study, optimize and install efficient optical 3D printing technologies for micro‐/nano‐processing of bioplastics derived from widely grown cereal cultures.

Research Council of Lithuania. Project (Research groups projects): Subtractive and Additive Laser Micromachining Synergy for Transparent Microtechnologies (+Tech-) (No. S-MIP-17-99). Dr. D.  Paipulas. 2018–2020.

The aim of the project is to develop the hybrid femtosecond laser micromachining methods by combining two different manufacturing technologies thus expanding their technological potential. Up to now the subtractive and additive methods have been mostly cultivated separately. In the context of our project additive manufacturing includes optical printing of cross-linkable materials with sub-micrometer spatial resolution and arbitrary 3D architectures, which in turn are already successfully applied in photonic and microengineering applications. On the other hand, subtractive manufacturing covers precision free-form cutting, drilling, surface patterning and bulk modification of transparent materials (glasses) which are also widely used in the field of microtechnologies.

Research Council of Lithuania.  Control of Filamentation Phenomena by Means of Competing Quadratic and Cubic Nonlinearities (COFIL). Grant No. APP-8/2016. Prof. A. Dubietis. 2016–2018.

The aim of the project is to demonstrate efficient control of filamentation dynamics and related phenomena, such as pulse compression and supercontinuum generation in birefringent media by means of competing quadratic and cubic nonlinearities. The project actions include comprehensive theoretical, numerical and experimental studies of filamentation and supercontinuum generation dynamics in basic nonlinear crystals using broadly tunable ultrashort laser pulses and so accessing the regimes of normal and anomalous group velocity dispersion.

Main publication:

Šuminas, R., Tamošauskas, G., Jukna, V., Couairon, A., Dubietis, A. 2017. Second-order cascading-assisted filamentation and controllable supercontinuum generation in birefringent crystals. Optics Express, vol. 25, p. 6746–6756.

Research Council of Lithuania. Photonic Crystal Microchip Laser (FOKRILAS). Grant No. P-MIP-17-190. Dr. V. Purlys. 2017–2020.

Microchip lasers are preferable to their counterparts due to their compactness and energy efficiency, but they have one fundamental drawback - low beam quality, which greatly limits their laser radiation maximum brightness and limits the field of applications. Most approaches to increase beam quality proposed so far either significantly limit the maximum achievable output power, or at least greatly increase the dimensions of the system. The aim of the project is to create a compact photonic crystal microstructure capable to block the generation of higher order modes and thus significantly increase the quality of the microchip laser radiation.

Research Council of Lithuania. Student practical research activities:

Feasibility Study for the Laser Fabrication of Three-Dimensional Microstructured Scaffolds for Cells with Defined Architecture Out Of Biodegradable Pre-Polymers. Student E. Skliutas, supervisor Dr. S. Rekštytė.

Investigation of Optical 3D Printing for Microporous Scaffolds, Research and Optimization of their Biocompatibility. Student G. Grigalevičiūtė, supervisor Dr. M. Malinauskas.

Formation of the Femtosecond Light Beams Propagating in Curved Trajectories by Phase Masks Manufactured from Glass. Student M. Karpavicius, supervisor Prof. V. Sirutkaitis.

Generation of Broadband Terahertz Radiation Generation in Laser Created Air Plasma. Student Ž. Svirskas, supervisor Dr. V. Vaičaitis.

Measurement of Photonic Crystal Fiber Dispersion by the Use of XFROG. Student M. Kuliešaitė, supervisor Dr. V. Jarutis.

International Research Projects

7FP Project: Integrated European Laser Laboratories IV (LASERLAB-Europe IV). 2015–2019.

Vilnius University represented by Department of Quantum Electronics and Laser Research Centre is member of LASERLAB-EUROPE IV and was involved in two joint research activities: Innovative Laser Technologies (ILAT) and Biomedical Optics for Life Science Applications (BIOAPP), networking and providing of the Transnational Access. Within Transnational Access program, three research projects together with researchers from UK, France and Germany were performed. 

Visit project of Dr. F. Claeyssens (University of Sheffield).

As a demonstration of the direct laser writing 3D lithography capabilities, poly(glycerol sebacate)-methacrylate  (PGS-M), µm-scale 3D scaffold structures were fabricated using 2-photon polymerization and used for 3D cell culture. The tunable properties of PGS-M coupled with its enhanced processing capabilities make the polymer an attractive potential biomaterial for various future applications.

Visit project of Dr. E. Brasselet (University of Bordeaux)

Design and characterization of laser 3D lithography made orbital angular momentum (OAM) microstructures. Both optical and acoustic scale free-movable spinners (walkers-on-water) were modelled, fabricated and measured.

Visit project of Dr. I. Babushkin (Institute of Quantum Optics in Leibniz University of Hannover): Supercontinuum Generation in Air by Bichromatic Femtosecond Laser Pulses.

NATO Science for Peace and Security programme project: Nanostructures for Highly Efficient Infrared Detection (Vilnius University + Universitat Politecnica de Catalunya + Shizuoka University + Swinburne University of Technology + University of Economics and Technology). VU part project leader Dr. M. Malinauskas, Project info [https://www.researchgate.net/project/Nanostructures-for-Highly-Efficient-Infrared-Detection]. 2016–2019.

We first show that light can be gradually slowed down in the defect waveguide (WG), which is obtained by gradually changing the period of the surrounding woodpile photonic crystal (WPC) along the propagation direction. In result, the waveguide mode gradually approaches the band edge region, while this phenomenon has three consequences. First, the Fourier components of propagating wave will be spatially separated as each frequency will reach its zero velocity at different positions. Second, as the wave slows down, it will penetrate deeper into the surrounding cladding, thus increasing the coupling efficiency between the WG and a nearby placed resonator. Third, the high density of states near the band edge result in highly efficient light scattering of a nearby placed resonator, which in turn increases the quality factor of the interaction. Following this idea, the acceptor type cavities, which are tuned to the localized frequencies, are side-coupled to the WG at respective wave localization areas. Furthermore, drop channels have been introduced to read-out the trapped spectra, showing that the targeted frequencies can be detected selectively. Compared to previous studies, our approach has the advantages of low radiation losses, the absence of any reflection feedback and both enhanced quality factor and transmission of the captured light.

US Army grant: Enhanced Absorbtion in Stopped-Light Photonic Nanostructures: Application to Efficient Sensing (Vilnius University + Universitat Politecnica de Catalunya). Project coordinator Dr. M. Malinauskas. 2016–2018.

In this work we explore a possibility to apply ultrafast 3D laser nanolithography in conjunction with pyrolysis to acquire glass-ceramic 3D structures in micro- and nano-scale. Laser fabrication allows for production of initial 3D structures with relatively small (hundreds nm - µm) feature sizes out of SZ2080 hybrid material. Then, post-fabrication heating at 600^oC in Ar atmosphere decomposes organic part of the material leaving the glass-ceramic component of the hybrid. Resulting structures are uniformly shrunk by 40%. This brings us one step closer to fabricating highly efficient slow-light absorbers.

Contractual Research

Characterization of diffractive optical elements and microstructures in transparent materials using profilometer and SEM, Customer – Femtika, 2017.

Research of 2nd and 3rd harmonics characteristics of Femtokit modules, Customer – Optolita, 2017-02.

Laser fabrication of 2.5D polymeric microstructures over a large surface area, Customer - Altechna R&D, 2017-04.

Demonstration of the achievable resolution and repeatability of polymeric microstructures fabricated by laser multiphoton polymerization, Customer - Altechna R&D, 2017-05.

Fabrication of resolution bridges out of SZ2080 pre-polymer by laser multiphoton polymerization, Customer - Altechna R&D, 2017-06.

Feasibility study of structuring complex geometry 3D polymeric microstructures by laser multiphoton polymerization, Customer - Altechna R&D, 2017-07.

Research of samples using profilometry and topography, Customer – Vilnius Gediminas Technical University, 2017-08.

Profile measurements of holes and grooves using profilometer, Customer - Altechna R&D, 2017-09.

Sample development using a critical point dryer (CPD), Customer - Altechna R&D, 2017-12.

MAIN R&D&I (RESEARCH, DEVELOPMENT AND INNOVATION) PARTNERS

Swinburne University of Technology, Centre for Micro-Photonics (H34), Hawthorn, (Australia)
UPC (Universitat Politechnica de Catalunya), Departament de Fisica i Enginyeria Nuclear, Terrassa (Spain)
Institut Fresnel-CNRS UMR 7249-Equipe ILM, Escole Centrale Marseille-Aix Marseille Universite (France)
Laboratoire des Solides Irradiés, Ecole Polytechnique, Palaiseau (France)
Light Conversion, Ltd. (Lithuania)
CNISM and Dipartimento di Scienza e Alta Tecnologia, University of Insubria, Como (Italy)
University of Patras, Physics Department, Laser, Nonlinear and Quantum Optics Labs, Rio Patras (Greece)
Centre de Physique Théorique, CNRS, Ecole Polytechnique, Université Paris-Saclay, Palaiseau (France)
University of Bordeaux, Laboratoire Ondes et Matière d’Aquitaine (LOMA), Talence (France)
University of Sheffield, Department of Materials Science and Engineering, Sheffield (United Kingdom)
Belarusian State Univerisity, Research Institute of Physical Chemical Problems, Minsk (Belarus)
Institute of Quantum Optics, Leibniz University of Hannover, D30167 Hannover (Germany)

OTHER SCIENTIFIC ACTIVITIES

Dr. M. Malinauskas –

• associate editor of the Optics Express (OSA);
• scientific committee member at Photonics West (SPIE);
• referee of H2020 programme ICT projects (EU) 2017.

Prof. V. Sirutkaitis –

• member of International Program Committee of Pacific-Rim Laser Damage Conference PLD’17, 21–24 May, 2017, Shanghai P. R. (China).

 

APPLIED ELECTRODYNAMICS AND TELECOMMUNICATION INSTITUTE

3 Saulėtekio, LT - 10257 Vilnius

Tel. 223 4536

E-mail:

Head - Prof. Habil. Dr. Jūras Banys

STAFF

Professors: Habil. Dr J. Banys, Habil. Dr. J. Matukas, Habil. Dr. A. Kežionis, Dr. R. Grigalaitis, Dr. A. Lisauskas.
Associate professors: Dr. R. Aleksiejūnas, Dr. M. Ivanov, Dr. V. Jonkus, Dr. E. Kazakevičius, Dr. S. Pralgauskaitė, Dr. R. Rimeika, Dr. R. Sobiestijanskas, Dr. K. Svirskas, Dr. T. Šalkus, Dr. M. Žilinskas.
Lectures: Dr. R. Giriūnienė, Dr. S. Kazlauskas, E. Dr. Palaimienė, Dr. Č. Pavasaris, Dr. V. Venckutė, K. Ikamas, Dž. Jablonskas, Š. Svirskas, M. Šimėnas.
Research fellows: Dr. J. Macutkevič, Dr. J. Vyšniauskas, Dr. S. Lapinskas, Dr. A. Džiaugys, Dr. A. Bernotas,    Dr. S. Kazlauskas, Dr. V. Venckutė, Dr. S. Rudys, Dr. M. Kinka, J. Aleksandravičius.
Engineering staff:  A. Sereika, V. Adomaitis, Dr. Č. Pavasaris, A. Cesiul, J. Glemža, E. Zdaniauskis, M. Tretjak.
Doctoral students: D. Adamchuk, J. Aleksandravičius, J. Belovickis, S. Balčiūnas, A. Cesiul, S. Daugėla, J. Glemža, K. Ikamas, Dž. Jablonskas, I. Kranauskaitė, J. Krivochiža, R. Mackevičiūtė, D. Meisak, E. Palaimienė, D. Petrulionis, A. Plyushch, Š. Svirskas, M. Šimėnas, M. Tretjak, I. Zamaraitė, J. Zdanevičius.

RESEARCH INTERESTS

Laboratory of Microwave Spectroscopy:

Broadband dielectric spectroscopy of ferroelectrics and related materials, relaxation and phonon dynamic studies in order-disorder ferroelectrics, ferroelectric ceramics, dipolar glasses, relaxors, composite systems, liquids, metal-organic structures etc.

RESEARCH PROJECTS CARRIED OUT IN 2017

Projects Supported by University Budget

Broadband Dielectric and Ultrasonic Spectroscopy of Innovative Materials. Prof. J. Banys. 2014–2018.

Dielectric and ultrasonic studies of various ferroelectrics, relaxor ferroelectrics, multiferroics, nanosized materials and inorganic and organic composites have been carried out. It was shown that in the most cases interesting and important information can be extracted from these investigations for the fundamental understanding as well as for the possible applications in today’s and future advanced devices and/or technologies.

Investigation of Technological Preparation Conditions and Ionic Transport Peculiarities in Solid Electrolyte Thin Films, Thick Films and Bulk Ceramics. Dr. T. Šalkus. 2016–2020.

The aim of the project is to find technological conditions for oxygen-ion conducting thin film growth by pulsed laser deposition and preparation of thick solid electrolyte films. The films and bulk ceramics of various solid electrolytes are characterized by impedance spectroscopy in the broadband frequency range and high temperatures up to 1000 K.

Main publications:

Kazlauskas, S., Kazakevičius, E., Kežionis, A. 2017. Electrical properties of scandia- and ceria-stabilized zirconia ceramics. Solid State Ionics, vol. 310, p. 143–147.

Emery, J., Šalkus, T., Barré, M. 2017. NMR Investigations in Li_1.3Al_0.3Ti_1.7(PO₄)₃ ceramics part III: local dynamical aspect seen from aluminum and phosphorus sites. The Journal of Physical Chemistry C, vol. 121, p. 246−254.

Daugėla, S., Šalkus, T., Kežionis, A., Venckutė, V., Valdniece, D., Dindune, A., Barre, M., Orliukas, A.F. 2017. Anomalous temperature-dependent electrical properties of Na₂MnP₂O₇. Solid State Ionics, vol. 302, p. 72–76.

Orliukas, A.F., Venckutė, V., Daugėla, S., Kežionis, A., Dindune, A., Valdniece, D., Ronis, J., Lelis, M., Mosiałek, M., Šalkus, T. 2017. Synthesis, structure and impedance spectroscopy of NaCsZn_0.5Mn_0.5P₂O₇ pyrophosphate ceramics. Solid State Ionics, vol. 302, p. 92–97.

Electromagnetic Methods for Increasing Spectral Efficiency of Radio Communication Systems. Dr. K. Svirskas. 2014–2018.

Complexity of wireless network research problems requires close comparison of experimental measurements with numerical simulations. For this purpose simulation framework for MIMO LTE network performance analysis is being used. The core of this environment consists of cloud-based virtual server environment, allowing interactively share results between team members and run massive simulations, for example, antena analysis, radio propagation channel, radio interference estimation problems. Simulations are based on statistical Monte Carlo algorythm, implemented using GNU Octave and Python numerical libraries.

Telecommunications Research centre started analysis project for the Communications Regulatory Authority of Lithuania on the compatibility between upcoming WiFi networks and existing satellite services, point-to-point wireless networks and ultra-wide band systems in 6 GHz frequency band.

Internship at University of Bologna, research project Localization of Objects in Space through RF Tags for European Space Agency (ESA), focusing on signal processing methods.

Main publications:

Costanzo, A., Dardari, D., Aleksandravicius, J., et al. Energy autonomous UWB localization. IEEE Journal of Radio Frequency Identification, to appear (accepted)

Aleksiejunas, R. 2017. Spatially consistent LOS/NLOS state model for statistical Monte Carlo simulations. IRACON, COST, May 29–31, Lund (Sweden).

Aleksandravicius, J., Decarli, N., Guerra, A., Dardari, D. 2017. High-accuracy localization of backscattering UWB tags: implementation and experimental results. IEEE International Conference on RFID Technology and Applications (RFID-TA), Warsaw (Poland).

Noise Characteristics Investigation of Quantum Structure Devices Employed in Telecommunication Systems. Prof. J. Matukas. 2016–2018.

Comprehensive investigation of materials and devices employed in telecommunication systems have been carried out: low frequency noise characteristics, responsivity of detectors and radiation characteristics of sources have been measured and analysed. Devices under investigation were: GaN, Si and graphene based diodes and transistors operating as detectors of terahertz radiation, GaSb based semiconductor lasers for mid-infrared radiation, materials with carbon nanoparticles. The main noise origins in these structures are thermal noise and generation-recombination, also 1/f-type fluctuations. Charge carrier transport mechanisms, influence of growth quality and device design to the operation characteristics of investigated devices were evaluated.

Main publications:

Glemža, J., Pralgauskaitė, S., Palenskis, V., Matukas, J. 2017. Low-frequency noise investigation of 2–3 µm GaSb-based laser diodes. Solid State Electron., vol. 133, p. 70–77; doi: 10.1016/j.sse.2017.05.002.

Pralgauskaitė, S., Matukas, J., Tretjak, M., Macutkevic, J., Banys, J., Selskis, A., Cataldo, A., Micciulla, F., Bellucci, S., Fierro, V., Celzard, A. 2017. Resistivity and low-frequency noise characteristics of epoxy-carbon composites. Journal of Applied Physics, vol. 121, p. 114303.

Zamaraite, I., Matukas, J., Pralgauskaite, S., Vysochanskii, Yu., Banys, J., Dziaugys, A. 2017. Low-frequency noise characteristics of lamellar ferrielectric crystal CuInP₂S₆ at the phase transition. Journal of Applied Physics, vol. 122, p. 024101; doi: 10.1063/1.4992813.

Ikamas, K., Lisauskas, A., Boppel, S., Hu, Q., Roskos, H. G. 2017. Efficient detection of 3 THz radiation from quantum cascade laser using silicon CMOS detectors. Journal of Infrared Millimeter and Terahertz Waves, vol. 38, p. 1183–1188; doi: 10.1007/s10762-017-0407-9.

Research of the Beginnings of the Baltic Identity.

National Research Projects

Research Project: Compact Integrated THz Components and Spectroscopic THz Imaging Systems of the National Program Towards Future Technologies. Prof. A. Lisauskas. 2016– 2018.

In last two decades the field of Terahertz (THz) physics and technology experiences tremendous growth, as it found the potential applications in such fields as space research, security, drugs control, medical and biological imaging, quality control in industry to name just a few. However, compact and effective THz detectors as well as THz optic components still remain an important issue. Commercial THz detectors available in THz market are based on quite slow optoacoustic, pyro-electric, and bolometric effects. Highest drawback of such devices relates to their long response time, sensitivity to mechanic and acoustic disturbances, bulky dimensions and high price. The main aim of the project is to develop compact THz components and spectroscopic THz imaging systems. Antenna-coupled field effect transistors and asymmetric geometry diodes will be employed as sensors up to 4 THz.

Main publications:

Zdanevicius, J., Ikamas, K., Matukas, J., Lisauskas, A., Richter, H., Hubers, H.-W., Bauer, M., Roskos, H. G. 2017. TeraFET detector for measuring power fluctuations of 4.75-THz QCL-generated radiation.  IEEE Xplore, International Conference on Noise and Fluctuations (ICNF), Vilnius, p. 1–4.

Vyšniauskas, J., Lisauskas, A., Bauer, M., Čibiraitė, D., Matukas J., Roskos, H. G. 2017. Hydrodynamic modelling of terahertz rectification in AlGaN/GaN high electron mobility transistors. The 20th International Conference on Electron Dynamics in Semiconductors, Optoelectronics and Nanostructures (EDISON 20), July 16–19, 2017 Buffalo. IOP Conf. Series: Journal of Physics: Conf. Series, vol. 906, p. 012023; doi:10.1088/1742-6596/906/1/012023

Cibiraite, D., Bauer, M., Rämer, A., Chevtchenko, S., Lisauskas, A., Matukas, J., Krozer, V., Heinrich, W., Roskos, H. G. 2017. Enhanced performance of AlGaN/GaN HEMT-Based THz detectors at room temperature and at low temperatures. 42nd International Conference on Infrared, Millimeter and Terahertz Waves, August 27–September 01, Cancun (Mexico), IEEE Xplore, 978-1-5090-6050-4/17, IEEE.

Vyšniauskas, J., Lisauskas, A., Matukas, J. 2017. Terahercų detekcijos AlGaN/GaN tranzistoriuose hidrodinaminis modeliavimas (Hydrodynamic simulation of terahertz detection in AlGaN/GaN transistors). Proc. of 42nd Conference of the Lithuanian National Physics, p. 282, October 4–6 2017, Vilnius.

International Research Projects

MSCA-RISE-2014: Marie Skłodowska-Curie Research and Innovation Staff Exchange Contractual Research Project: Tuneable Multiferroics Based on Oxygen Octahedral Structures TUMOCS. Prof. J. Banys. 2015–2018.

The main objective of the project is development of new lead-free multiferroic materials through preparation, investigation, and optimization of Bi-containing oxygen-octahedral systems with paramagnetic ions involved: metastable perovskites and layered double hydroxides (LDHs). Thin films of BLSFO were produced and investigated. They are quite heavily doped and show metallic-type behavior. Pellets of LDHs were investigated under vacuum conditions (25–300 K). Dielectric spectroscopy showed an anomaly in 75–150 K range, which is somewhat influenced by magnetic field.

Main publication:

Salak, A. N., Khalyavin, D. D., Zamaraite, I., Stanulis, A., Kareiva, A., Shilin, A. D., Rubanik, V. V., Radyush, Y. V., Pushkarev, A. V., Olekhnovich, N. M., Starykevich, M., Grigalaitis, R., Ivanov, M., Banys, J. 2017.  Metastable perovskite Bi1-xLaxFe0.5Sc0.5O3 phases in the range of the compositional crossover. Phase Transit., vol. 90:9, p. 831–839.

Bilateral Lithuanian-Japanese partnership projects: Dielectric and Piezoelectric Enhancements of New Nano-Structured Ceramics with High-Density Artificially-Made Extrinsic MPB Structures. Assoc. Prof. M. Ivanov. 2016–2018.

One of the main objectives in 2017 was to make the majority of characterisation and analysis. This was achieved along with dissemination of the results. The obtained results were presented in various conferences in Europe, USA and Japan; one paper was published and one accepted for publication. Thus, the achievements are more than was planned.

Main publication:

Balčiūnas, S., Ivanov, M., Banys, J., Wada, S. 2017. Dielectric properties of BaTiO3-KNbO3 composites. Ferroelectrics, vol. 512, p. 8–13.

Bilateral Lithuanian-Japanese partnership projects: Ultrabroadband Dielectric Spectroscopy of Relaxor Ferroelectrics. Prof. J. Banys. 2016–2018.

The main focus of the project in 2017 was the investigation of nonlinearities in PMN-17PT single crystals. The response of the single crystal was measured at high fields and ferroelectric and electromechanical hystersis loops were investigated. These investigations revealed that polar nanoregions start percolating at certain temperatures forming the stable ferroelectric domains. The whole dipolar dynamics in the system is of order-disorder type.

Main publications:       

Svirskas, Š., Kojima, S., Banys, J. 2017. Broadband dielectric spectroscopy of Pb-based relaxor ferroelectric (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 with intermediate random fields. Journal of Applied Physics, 121, 134101.                                                                                                                              

Helal, Md Al, Aftabuzzaman, Md, Svirskas, S., Banys, J. and Kojima, S. 2017. Temperature evolution of central peaks and effect of electric field in relaxor ferroelectric 0.83Pb(Mg1/3Nb2/3)O3–0.17PbTiO3 single crystals. Japanese Journal of Applied Physics, 56, 10S.

Joint Lithuanian-Latvian-Taiwan project: Nano Architectonics of Metal-Organic Frameworks(MOFs): Design, Dielectric Property and Organic Catalysis. Prof. R. Grigalaitis. 2017–2019.

The aim of this project is the synthesis of MOF structures via de novo procedure with different catalysts incorporated and the investigation of their dielectric and other functional properties. During 2017 the dielectric properties of ZIF-90 and UIO-66 MOFs were examined in different environment conditions. The peculiarities of the electrical response to various gasses was determined which further can lead to the development of novel gas sensing devices.

Bilateral Lithuanian-Belorussian project: Multifunctional Ceramics with SiC and Carbon Nanoparticles. Dr. J. Macutkevič. 2017–2018.

The main result of the project are produced ceramics with SiC and carbon nanoinclusions, which are stable till very high temperatures (1700°C) and exhibit strong electromagnetic wave absorbtion. Electrical studies have shown that the frequency dependence of electrical properties is caused by Maxwell-Wagner relaxation and the temperature dependence of electrical conductivity exhibit non-Arhenius behaviour. The electrical percolation threshold, for ceramics with SiC nanotubes is 35 wt%, while for round SiC nanoparticles it is close to 40 wt%.

Main publications:

Kranauskaite, I., Macutkevic, J., Borisova, A., Martone, A., Zarrelli, M., Selskis, A., Aniskevich, A., Banys, J. 2017. Enhancing electrical conductivity of MWCNT/epoxy composites by GNP particles. Lithuanian Journal of Physics, p. 195–203.

Macutkevic, J., Belovickis, J., Otorgust, G., Dodiuk, H., Kenig, Sh., Samulionis, V., Banys, J., Zak, A. 2017. Broadband dielectric and ultrasonic properties of WS2 nanotubes/polyurethane composites. Polymer Composites; https://doi.org/10.1002/pc.24554.

Bilateral Lithuanian-French Gilbert project: Dielectric and Electric Properties of Carbon Spheres and Mesoporous Carbon. Dr. J. Macutkevič. 2017–2018.

The main results of the project are determined electromagnetic properties of hollow carbon spheres and mesoporous carbon with various sizes of pores. All these materials are suitable for electromagnetic shielding.

Main publication:

Letellier, M., Macutkevic, J., Kuzhir, P., Banys, J., Fierro, V., Celzard, A. 2017. Electromagnetic properties of model vitreous carbon foam. Carbon, vol. 122, p. 217–227.

Bilateral Lithuanian-French Partnership project: Elaboration of Composite Solid Electrolytes and their Application for Electrochemical Devices.

The project is devoted to elaborate new composite materials on the basis of NASICON and LAMOX solid electrolyte families by combining crystalline and amorphous phases. The aim of the investigation is to understand mechanisms of ionic transport in these materials and to improve their electrical properties.

 

MAIN R&D&I (RESEARCH, DEVELOPMENT AND INNOVATION) PARTNERS

Institute of Solid State Physics of University of Latvia (Latvia)
Leipzig University (Germany)
University of Duisburg-Essen (Germany)
University of Aveiro (Portugal)
National Taiwan University (Taiwan)
University of Yamanashi (Japan)
University of Tsukuba (Japan)

                                                   

INSTITUTE OF THEORETICAL PHYSICS AND ASTRONOMY

3 Saulėtekio, LT-10257 Vilnius
Tel. 223 4636, fax 223 4637
E-mail: tfai @ tfai.vu.lt

Director – Habil. Dr. Gediminas Juzeliūnas

STAFF

Professors: Prof. Dr. E. Anisimovas (part-time), Dr. A. Kučinskas (part-time), Prof. Dr.  V. Vansevičius (part-time).
Research professors: Habil. Dr. A. Bartkevičius (affiliated), Dr. K.Černis, Dr. A. Deltuva, Habil. Dr. Prof. G. Gaigalas, Dr. V. Gontis, Doc. Dr. V. Jonauskas, Habil. Dr. G. Juzeliūnas, Habil. Dr. R. Karazija (affiliated), Habil. Dr. B. Kaulakys, Dr. A. Kučinskas, Dr. J. Ruseckas, Habil. Dr. Emeritus V. Straižys, Habil. Dr. G. Tautvaišienė, Habil. Dr. K. Zdanavičius (affiliated).
Associate professors: Dr. A. Bridžius (part-time), Dr. T. Gajdosik, Dr. D. Narbutis (part-time), Dr. R. Stonkutė (part-time), Dr. K. Zubovas (part-time).
Senior research fellows: Doc. Dr. A. Acus, Dr. R. Janulis, Dr. A. Juodagalvis,   Habil. Dr. V. Gineitytė (affiliated), Dr. R. Karpuškienė, Dr. A. Kazlauskas, Dr. R. Kisielius, Dr. S. Kučas, Dr. A. Kupliauskienė, Prof. Dr. E. Norvaišas, Dr. E. Pakštienė, Dr. V. Regelskis, Dr. J. Sperauskas, Dr. D. Šatkovskienė (affiliated), Dr. J. Tamulienė, Dr. A.  Vektarienė, Dr. G. Vektaris, Dr. J. Zdanavičius.
Research fellows: Dr. J.  Armaitis (also Marie Currie Fellow),  Dr. Y. Chorniy , Dr. V. Čepas (part-time), Dr. V. Dobrovolskas, Dr. A. Drazdauskas, Dr. D. Jurčiukonis, Dr. R. Juršėnas, Dr. H. R. Hamedi,   Dr. A. Kynienė, Dr. A. Kononovičius, Dr. V. Kudriašov (part-time), Dr. Š. Masys, Dr. M. Maskoliūnas, Dr. Š. Mikolaitis, Dr. R. Minkevičiūtė, Dr. A. Mekys (part-time),  Dr. A. Momkauskaitė, Dr. V. Novičenko, Dr. L. Radžiūtė, Dr. P. Rynkun, Dr. E. Stonkutė, Dr. V. Šimonis.
Junior research fellows: T. Andrijauskas, A. Černiauskas, V. Deveikis, Dr. V. Juknevičius (part-time), Dr. R. Kazakevičius (part-time), Dr. J. Klevas ,  M. Macijauskas (part-time), K. Milašius (part-time),  S. Raudeliūnas (part-time).
Doctoral students: J. Bialopetravičius, V. Dūdėnas, G. Kerevičius, E. Kolomiecas, J. Koncevičiūtė, Ž. Misikonytė, S. Pakalka, M. Račiūnas, C. Viiscasillas Vazquez, G. Žlabys
Lecturer:  S. Lovčikas.
Engineer: M. Račiūnas (part-time).
Technicians:  V. Bagdonas (part-time), L. Klebonas (part-time), G. Žlabys (part-time).

RESEARCH INTERESTS

Galactic structure and chemodynamical evolution
Chemical composition and mixing phenomena in stellar atmospheres
Hydrodynamical phenomena and non-equilibrium radiative transfer in stellar atmospheres
Stellar asteroseismology
Planet hosting stars and exoplanet transits
Structure and evolution of galaxies
Search and positional observations of comets and asteroids
Theoretical atomic spectroscopy
Quantum many-body theory
Algorithms and computer programs for plasma physics, astrophysics and other fields
Application of quantum mechanics and electrodynamics for transitions in atoms, molecules and molecular complexes
Interactions of atoms and molecules with electrons and radiation
Spectroscopic characteristics of the molecular compounds
Theoretical investigation of crystalline and electronic structure of perovskite crystals
Development of algebraic techniques for nuclear and particle physics
Investigation of electroweak vector bosons in pp collisions
Investigation of scattering processes in few-body nuclear systems
Quantum optics and ultra-cold atoms
Bose-Einstein condensates
Condensed matter systems
Quantum chemistry
Condensed molecular structures
Econophysics and physics of finance
Fluctuations and noise, theory of 1/f noise

RESEARCH PROJECTS CARRIED OUT IN 2017

Projects Supported by University Budget

Stellar Chemical Composition and Asteroseismic Activity in the Milky Way Galaxy. Habil. Dr. G. Tautvaišienė. 2016–2020.

We studied the chemical evolution of the thick and thin discs of the Galaxy and concluded that the thick disc has formed on a time-scale of accretion of 0.1 Gyr, whereas the thin disc formed on a time-scale of 7 Gyr in the solar region. A gap in star formation between the thick and thin disc formation of several hundreds of Myr should be present. We also studied the lithium, sulphur, and zinc enrichment histories of the Galactic thick and thin discs as well as the metallicity dependence of the [Y/Mg]-age relation for solar-type stars. Using the Moletai Astronomical Observatory telescopes, we studied the exoplanet hosting star HAT-P-23 and found two new exoplanets of hot-jupiter type rotating around it.

Main publications:

Grisoni, V., Spitoni, E., Matteucci, F., Recio-Blanco, A., de Laverny, P., Hayden, M., Mikolaitis, Š. and Worley, C. C. 2017. The AMBRE project: chemical evolution models for the Milky Way thick and thin discs. Monthly Notices of the Royal Astronomical Society, vol. 472, p. 3637–3647.

Hayden, M. R., Recio-Blanco, A., de Laverny, P., Mikolaitis, S., and Worley, C. C. 2017. The AMBRE project: The thick thin disk and thin thick disk of the Milky Way. Astronomy & Astrophysics, vol. 608, id.L1, 5 p.

Feltzing, S., Howes, L. M., McMillan, P. J., Stonkutė, E. 2017. On the metallicity dependence of the [Y/Mg]-age relation for solar-type stars. Monthly Notices of the Royal Astronomical Society: Letters, vol. 465, L109–L113.

Star Formation and Dust Clouds in the Orion and Perseus Arms of the Galaxy. Prof. V. Straižys. 2016–2020.

Interstellar extinction in the direction of dark clouds TGU H989 P2 and TGU H989 P3 within the dust ring in Camelopardalis and containing the open cluster King 7, was investigated using about 960 stars observed in the seven-colour Vilnius system and the 2MASS and WISE infrared photometric systems. Spectral and luminosity classes, interstellar reddenings and distances were determined. Dust distribution in the area was compared to the distribution of molecules CO taken from the Dame et al. Survey. The Gaia Data Release 1 prallaxes were applied for determination of distances. 80 young stellar objects have been discovered. In the area of young open cluster NGC 2264 the catalogue of young stellar objects, containing about 600 objects, was analysed to determine the cluster membership, interstellar reddenings, extinctions and ages. 

An in-depth study of the formation of OH UV spectral lines in the atmosphere of a metal-poor red giant star HD 122563 was carried out using 3D hydrodynamical CO⁵BOLD model atmosphere. It was shown that the formation OH UV lines are prone to large 3D effects; besides, chromospheric layers play an important role in the formation of these lines. Because of this, oxygen abundances obtained using 3D hydrodynamical model atmosphere and different oxygen abundance indicators (OH UV & IR lines, the forbidden [O I] line) are more accurate and reliable than those determined using classical 1D hydrostatic model atmospheres.

Main publication:

Prakapavičius, D., Kučinskas, A., Dobrovolskas, V., Klevas, J., Steffen, M., Bonifacio, P., Ludwig, H.-G., Spite, M. 2017. Three-dimensional hydrodynamical CO5BOLD model atmospheres of red giant stars. V. Oxygen abundance in the metal-poor giant HD 122563 from OH UV lines. Astronomy & Astrophysics, 599, A128.

Stochastic Effects in Stellar Systems. Prof. Dr. V. Vansevičius. 2014–2018.

A detailed study of the Leo A galaxy was performed using ground (Subaru, National Astronomical Observatory of Japan) and space based observations (Hubble Space Telescope). Spatially resolved star formation history of Leo A galaxy was derived. Evolutionary parameters of 1363 star clusters in the Andromeda galaxy were determined based on Hubble Space Telescope photometric observations. 336 radial velocity observations of K-M dwarfs in the solar vicinity were performed using VUES spectrograph at the Molėtai Astronomical Observatory. Variability periods of 7 PPNe stars (35-135 days) were derived based on 1517 radial velocity measurements and it was demonstrated that all monitored PPNe do not have secondary components more massive than 0.2 solar masses. We determined the properties of turbulent gas and its fragmentation in galaxy bulges subjected to AGN feedback, discovered that AGN seem to have a critical luminosity, which gives the strongest enhancement of star formation in the host galaxy.

Main publications:

de Meulenaer, P., Stonkutė, R., Vansevičius, V. 2017. Deriving physical parameters of unresolved star clusters. V. M 31 PHAT star clusters. Astronomy and Astrophysics, 602, A112.

Hrivnak, B. J., Van de Steene, G., Van Winckel, H., Sperauskas, J., Bohlender, D., Lu, W. 2017. Where are the binaries? Results of a long-term search for radial velocity binaries in proto-planetary nebulae. Astrophysical Journal, vol. 846, p. 96.

Zubovas, K., Bourne, M. A. 2017. Do AGN outflows quench or enhance star formation? Monthly Notices of the Royal Astronomical Society, vol. 468, p. 4956–4967.

Astrometry and Photometry of Small Solar-System Bodies. Dr. K. Černis. 2016–2020.

Twenty-seven new asteroids have been discovered. A new precise orbit of the Distant object (463368) 2012 VU85 was determined. Precise orbits were calculated for our earlier discovered 99 objects at the Molėtai Observatory in 2010–2012. We published 5759 astrometric positions of 1383 asteroids. Near Earth Objects, TNO, Main Belt, Centaurs asteroids and comets were observed with the 0.35/0.51 m Maksutov telescope (Molėtai Observatory), with the 0.80/1.20 m Schmidt telescope (Baldone Observatory, Latvia), and with the 1.8 m Vatican telescope (Mt. Graham, Arizona, U.S.A.). Five asteroids were named after Steponas Darius, Stasys Girėnas, Kučinskas, Bridžius and Trakai.

Main publications:

Wlodarczyk, I., Černis, K., Boyle, R.  2017.  Discovery, orbit and orbital evolution of the Distant object (463368) 2012 VU85. Acta Astron., vol.  67, p. 81–102.

Wlodarczyk, I., Černis, K., Zdanavičius J. 2017. Observational data and orbits of the asteroids discovered at the Molėtai Observatory in 2010–2012. Open Astron., vol. 26, p. 35–45.

Černis, K. Astrometric observations of 22 asteroids (87 positions) in Molėtai Astronomical Observatory (Code 152). M.P.C. 103152  (2017 Mar. 12).

Investigation of the Spectroscopic Characteristics of Complex Atoms and their Derivatives. Dr. A. Kupliauskienė. 2012–2018.

The energies and electron-impact excitation cross sections of Sr ion from 4p subshell are calculated in the Dirac-Fock-Slater approximation. The classification of calculated energy levels is performed. The intensity spectrum of the Auger lines of Sr ion emitted following 4p-electron impact excitation of Sr atom via simultaneous ionization and excitation as well as excitation-autoionization processes is evaluated and used for the identification of experimental spectrum. The spectroscopic parameters of configurations 4p⁶4d³, 4p⁵4d⁶, and 4p⁶4d⁴f  of ion W^33¾ are calculated using the quasi-relativistic approach. Relativistic spin-photon (or else AME) interaction term is written in irreducible tensor form, provided that the radiation source is described by electronic transitions. As a result, it is shown that the atomic energy corrections increase for shortwavelengths (such as eg. 21 Å or shorter wavelengths of satellite lines) and large charge number. The most probable fragmentation pathways of the glutamate were determined. The structure and composition of the fragments were established.

Main publications:

Kupliauskienė, A., Kerevičius, G., Borovik, V., Shafranyosh, I., Borovik, A. 2017. The energy structure and decay channels of the 4p⁶-shell excited states in Sr. J. Phys. B: At. Mol. Opt. Phys., vol. 50, p. 225201.

Tamulienė, J., Noll, J., Frenzel, P., Rüffer, T., Jakob, A., Walfort, B. and Lang, H. 2017. Synthesis of [{AgO 2 CCH 2OMe(PPh 3 )} n ] and theoretical study of its use in focused electron beam induced deposition. Beilstein J. Nanotechnol., vol. 8, p. 2615.

Juršėnas, R. 2017. Irreducible tensor form for the spin-photon coupling. Physics Letters A, vol. 381, p. 3295.

Investigation of Ordered and Unordered Atomic Systems. Dr. V. Jonauskas. 2014–2018.

It is shown that triple ionization (TI) of the Se2+ ion is mainly formed in two ways: (i) Auger cascade following single ionization of the 3p shell and (ii) direct double ionization with subsequent autoionization. The study reveals negligible contribution of the direct TI by electron-impact to the process. Single ionization by electron impact of the Se3+ ion is investigated in the Dirac-Fock-Slater approximation. Contributions from direct ionization, excitation-autoionization, and resonant-excitation double-autoionization processes are taken into account. It is shown that ionization-ionization and ionization-excitation-ionization processes can play the significant role in the double ionization of Se3+ ions. The first-principles calculations performed within the hybrid density functional theory scheme indicate that under weak tensile strain SrRuO3 thin films prefer the Cmcm rather than the I4/mmm lattice, allowing to conclusively dispel the uncertainty the experimentalists have previously dealt with while trying to identify the crystalline structure of tensile strained SrRuO3.

Main publications:

Masys, Š., Jonauskas, V. 2017. The crystalline structure of SrRuO3: Application of hybrid scheme to the density functionals revised for solids. Lith. J. Phys., vol. 57, p. 78.

Cashman, F. H., Kulkarni, V. P., Kisielius, R., Ferland, G. J., Bogdanovich, P. 2017. Atomic data revisions for transitions relevant to bservations of interstellar, circumgalactic, and intergalactic matter. The Astrophysical Journal Supplement Series, vol. 230, p. 8.

Aggarwal, K. M., Bogdanovich, P., Keenan, F. P., Kisielius, R. 2017. Energy levels and radiative rates for transitions in Fe V, Co VI and Ni VII. Atomic Data and Nuclear Data Tables, vol. 114, p. 1.

Correlaton and Relativistic Effects in Complex Atoms and Ions. Prof. G. Gaigalas. 2015–2019.

Employing multiconfiguration Dirac–Hartree–Fock method the excitation energies and lifetimes for the lowest 200 states and multipole transition data among these states are calculated for O-like ion, from Cr XVII to Zn XXIII. The data are useful for identification and deblending of new emission lines from the Sun and other astrophysical sources. The amount data is significantly increased for the n=3 states of several O-like ions of astrophysical interest, where experimental data are very scarce.

Main publications:

Wang, K., Jönsson, P., Ekman, J., Brage, T., Chen, Ch. Y., Fischer, Ch. F., Gaigalas, G., Godefroid, M. 2017. Comment on “Theoretical confirmation of the low experimental 3C/3D f-value ratio in Fe XVII”. Phys. Rev. Lett., vol. 119, p. 18930.

Wang, K., Jönsson, P., Ekman, J., Gaigalas, G., Godefroid, M. R., Si, R., Chen, Z.B., Li, S., Chen, C. Y., Yan, J. 2017. Extended calculations of spectroscopic data: energy levels, lifetimes, and transition rates for O-like ions from Cr XVII to Zn XXIII. Astrophysical Journal Supplement Series, vol. 229, p. 37.

Filippin, L., Bieroń, J., Gaigalas, G., Godefroid, M., Jönsson, P. 2017. Multiconfiguration calculations of electronic isotope-shift factors in Zn I. Phys. Rev. A 96, 0042502.

Theoretical Study of Light Nuclei and Elementary Particles. Dr. A. Deltuva. 2016–2020.

Nucleon transfer reactions in deuteron-deuteron collisions above breakup threshold were studied solving exact integral equations for four-body transition operators; differential cross sections, analyzing powers, and spin transfer coefficients calculated using realistic NN force models were found to be in good agreement with experimental data. Universal properties of the four-fermion system near the unitary limit have been determined, in particular, the parameters of the effective range expansion for the fermionic dimer-dimer scattering. Magnetic moments and magnetic dipole transition widths of all ground-state heavy hadrons were studied within a framework of the modified bag model. For the baryons containing three differently flavoured quarks, the effect of hyperfine mixing was taken into account. In order to minimize uncertainties in the calculation of the decay widths the additional care was taken to improve theoretical predictions for the energy of emitted photon (when available, the experimental data were used).

Main publications:

Deltuva, A., Fonseca, A. C. 2017.  Four-body calculation of  ²H(d,p)³H and ^\2H(d,n)³He  reactions above breakup threshold. Phys. Rev. C 95, 024003.

Deltuva, A. 2017. Universality in fermionic dimer-dimer scattering. Phys. Rev. A 96, 022701.

Dargys, A., Acus, A. 2017. Calculation of quantum Eigens with geometrical algebra rotors, advances. Applied Clifford Algebras, vol. 27 (1), p. 241–253; doi:10.1007/s00006-015-0549-6.

Optical and Kinetic Properties of Cold Atoms and Condensed Molecular Structures. Habil. Dr. G. Juzeliūnas, 2011–2017.

Propagation of a probe pulse was considered in an atomic medium characterized by a combined tripod and Lambda atom-light coupling scheme. It is demonstrated that dark states can be formed for such an atom-light coupling leading to the electromagnetic transparency and slow light. It is shown that generation of stable slow light optical solitons is possible in such a combined tripod and Lambda atomic system. An optical bistability was demonstrated for a four-level atomic system involving a Rydberg state illuminated by a probe and control laser fields. A way of creating the spin-orbit coupling in atomic-molecular Bose-Einstein condensates was demonstrated by combining the spin-dependent photoassociation and Raman coupling, which can lead to formation of topological excitations.

Main publications:

Hamedi, H. R., Ruseckas, J. and Juzeliūnas, G. 2017. Electromagnetically induced transparency and nonlinear pulse propagation in a combined tripod and Λ atom-light coupling scheme. J. Phys. B, 50, 185401.

Hamedi, H. R., Sahrai, M., Khoshsima, H. and Juzeliūnas, G. 2017. Optical bistability forming due to a Rydberg state. J. Opt. Soc. Am B, 34, 1923.

Liu, C. F., Juzeliūnas, G. and Liu, W. M. 2017. Spin-orbit coupling manipulating composite topological spin textures in atomic-molecular Bose-Einstein condensates. Phys. Rev. A, 95, 023624.

Evolution and Statistics of Complex Systems. Prof. B. Kaulakys. 2017–2021.

We have studied burst and inter-burst duration statistics as empirical test of a long-range memory in the financial markets. The concept of spurious memory in the non-equilibrium stochastic models of imitative behavior, based on the non-linear stochastic differential equations, is developed.  We have shown that Forex data with high probability exhibits spurious memory as empirical burst and inter-burst duration statistics can be reproduced by proposed model with Markov property. We have studied statistics of the Lithuanian parliamentary elections and shown that these statistics could arise from a simple herding model, which is also used in our works related to a long-range memory in the financial markets. We have shown that both Forex and our model of financial markets both exhibit spurious long-range memory.

Main publications:

Gontis, V. and Kononovicius, A. 2017. Burst and inter-burst duration statistics as empirical test of long-range memory in the financial markets. Physica A 483, 266.

Kononovicius, A. 2017.  Empirical analysis and agent-based modeling of Lithuanian parliamentary elections. Complexity 2017, 7354642.

Gontis, V. and Kononovicius, A. 2017. Spurious memory in non-equilibrium stochastic models of imitative behaviour. Entropy 19, 387.

National Research Projects

Research Council of Lithuania. Spectroscopic and Photometric Survey of Northern Sky for the ESA PLATO space mission (LAT-16019). Dr. Š. Mikolaitis. 2016–2018.

The PLATO Space Observatory of the European Space Agency is expected to find exoplanets that could be similar to planets in our solar system. To accurately access the properties of the planets, scientists have to know as much as possible about the star the planet is orbiting. We are acquiring this information (surface temperature, gravity, metallicity, chemical composition, variability information) for the northern PLATO fields using spectroscopic and photometric infrastructure at the Molėtai Astronomical Observatory, VU ITPA. High-resolution spectral observations have been carried out for 213 stars and photometric variability light curves obtained for 3604 stars.

Main publication:

Mikolaitis, Š., de Laverny, P., Recio-Blanco, A., Hill, V., Worley, C. C., de Pascale, M. 2017. The AMBRE project: Iron-peak elements in the solar neighbourhood. Astronomy & Astrophysics, vol. 600, id.A22.

Research Council of Lithuania. Towards Realistic Stellar Model Atmospheres: Magnetic Fields, Molecules, and Non-Equilibrium Radiative Transfer in Stellar Atmospheres (MIP–089/2015). Dr. A. Kučinskas. 2015–2018.

We constructed a first 3D hydrodynamical model of a red giant star with the chromosphere. We have shown that shock waves propagating in the chromosphere alter the intensity and shape of the chromospheric spectral line profiles, and lead to a significantly higher flux in the UV. These properties can not be recovered using classical 1D hydrostatic model atmospheres. The obtained results demonstrate that chromospheres are prominent in red giant stars and play an important role in shaping their observable properties. We have also discovered that stars belonging to different stellar generations in the globular cluster 47 Tuc have very similar potassium abundance. We found no statistically significant relations between the abundances of potassium and other light elements, such as sodium and magnesium. In addition, there were no abundance trends with the distance from the cluster center, nor any statistically significant relations between the abundance/abundance ratios and absolute radial velocities of individual stars. All these facts suggest the similarity of K abundance in stars that belong to different generations in 47 Tuc, which, in turn, may hint that evolution of K in this particular cluster was unrelated to the nucleosynthesis of Na and/or Mg.

Main publications:

Wedemeyer, S., Kučinskas, A., Klevas, J., Ludwig, H.-G. 2017. Three-dimensional hydrodynamical CO5BOLD model atmospheres of red giant stars VI. First chromosphere model of a late-type giant. Astronomy & Astrophysics, 606, A26.

Černiauskas, A., Kučinskas, A., Klevas, J., Prakapavičius, D., Korotin, S., Bonifacio, P., Ludwig, H.-G., Caffau, E., Steffen, M. 2017. Abundances of Na, Mg, and K in the atmospheres of RGB stars of Galactic globular cluster 47 Tucanae. Astronomy & Astrophysics, 604, A35.

Research Council of Lithuania. Spectroscopic Survey of Carbon, Nitrogen and Oxygen in Stars of the Galactic Open Clusters (MIP-082/2015). Dr. Habil. G. Tautvaišienė. 2015–2018.

We traced the radial distributions of abundances of chemical elements produced through different nucleosynthetic channels – the alpha-elements O, Mg, Si, Ca and Ti, and the iron-peak elements Fe, Cr, Ni and Sc – by use of the Gaia-ESO IDR4 results for open clusters and young-field stars. We found that the chemo-dynamical model, with the new generation of metallicity-dependent stellar yields for massive stars, is able to reproduce the observed spatial distributions of abundance ratios, in particular the abundance ratios of [O/Fe] and [Mg/Fe] in the inner disc (5 kpc<RGC<7 kpc), with their differences, that were usually poorly explained by chemical evolution models.

Main publications:

Tang, B., Tautvaišienė, G., Drazdauskas, A., Ženovienė, R., et al. 2017. The Gaia-ESO survey: the inner disk intermediate-age open cluster NGC 6802.  Astronomy & Astrophysics, vol. 601, id.A56, 16 p.

Magrini. L., Tautvaišienė, G., et al. 2017. The Gaia-ESO Survey: radial distribution of abundances in the Galactic disc from open clusters and young-field stars. Astronomy & Astrophysics, vol. 603, id.A2, 20 p.

Research Council of Lithuania. Theoretical Study of Three-particle Nuclear Reactions (No. MIP-094/2015). Dr. A. Deltuva. 2015–2017.

Nuclear reactions in systems consisting of two nucleons and nuclear core were described using exact three-body Faddeev theory for transition operators   in the momentum-space partial-wave representation. ²⁰O(d,p)²¹O  transfer reactions were described  including the vibrational excitation of the  ²⁰O core. The experimental cross section data at 10.5 MeV/nucleon beam energy for the ²¹O ground state 5/2+ and excited state 1/2+ were quite well reproduced by the calculations with the core excitation.  At higher energies core-excitation effects were found to be very different for reactions with the orbital angular momentum transfer l=0 and l=2, suppressing the cross sections for the former and enhancing for the latter.

Low-energy neutron–¹⁹C scattering was studied in the three-body n + n + ¹⁸C model using a realistic nn potential and a number of shallow and deep n–¹⁸C potentials.  For the elastic n–¹⁹C scattering in the J = 0+ partial wave the signatures of the Efimov physics were confirmed for both shallow and deep models, but  with clear quantitative differences between them, indicating the importance of a proper treatment of deeply-bound Pauli-forbidden states. 

Main publications:

Deltuva, A., Jurčiukonis, D., Norvaišas, E. 2017. Core-excitation effects in ²⁰O(d,p)²¹O transfer reactions: Suppression or enhancement? Phys. Lett. B 769, 202.

Deltuva, A. 2017. Neutron-¹⁹C scattering: Towards including realistic interactions. Phys. Lett. B 772, 657.

Research Council of Lithuania. Novel Optical Lattices (No. MIP-86/2015). Habil. Dr. G. Juzeliūnas. 2015–2018.

Superfluidity properties have been investigated for degenerate gas of Fermi of atoms in a laser-assisted bilayer system providing the two-dimensional spin-orbit coupling (SOC). It is demonstrated that a Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state appears in the regime of small to moderate atom-light coupling. In contrast to the ordinary SOC, the FFLO state emerges in the bilayer system without adding any external fields or spin polarization. As the atom-light coupling increases, the system can transit from the FFLO state to a topological superfluid state. These findings are confirmed by the Bogoliubov-de Gennes simulations with a weak harmonic trap added.

Main publication:

Wang, L. L., Sun, Q., Liu, W. M., Juzeliūnas, G. and  Ji, A. C. 2017. Fulde-Ferrell-Larkin-Ovchinnikov state to topological superfluidity transition in bilayer spin-orbit-coupled degenerate Fermi gases. Phys. Rev. A 95, 053628.

Research Council of Lithuania. Quantum Phases and Phase Transitions in Restricted-Geometry Condensates (No. APP-4/2016). Prof. Dr. E. Anisimovas. 2016–2019.

During 2017, the project continued its activities, focusing on Floquet engineering of artificial gauge fields, stabilization and detection of fractional quantum Hall states, and motion of wave packets in the presence of position-space, momentum-space and phase-space Berry curvature. In particular, it was demonstrated that in square lattices as small as 9x5 sites fractionally charged topological excitations could be induced using two complementary techniques: introduction of local potential offsets and threading a local flux tube through a single plaquette.

Main publications:

Novičenko, V., Anisimovas, E. and Juzeliūnas, G. 2017. Floquet analysis of a quantum system with modulated periodic driving. Phys. Rev. A 95, 023615.

Armaitis, J., Ruseckas, J. and Anisimovas, E. 2017. Phase-space curvature in spin-orbit-coupled ultracold atomic systems. Phys. Rev. A 95, 043616.

Research Council of Lithuania. Interstellar clouds and Star Forming in the Great Cygnus Rift of the Milky Way (S-MIP–17-74). Dr. S. A. Kazlauskas. 2017–2019.

The goal of this project is the investigation of a group of interstellar clouds and star forming regions (SFRs) located in the direction of the Great Cygnus Rift, between the Galactic longitudes 70–90 deg. Using the seven-colour Vilnius photometric system as well as astrometric data from the Gaia orbiting observatory we determine the distances and interstellar extinction to several young clusters located in this region. For determination of young stellar objects (YSOs) we also use data of the infrared photometric surveys 2MASS (Two-Micron All Sky Survey) and WISE (Wide-field Infrared Survey Explorer). The preliminary results of the investigation of the open cluster IC4996 will be presented at the 231^st meeting of the American Astronomical Society in January 2018. 

Research Council of Lithuania. Postdoctoral fellowship: Physical Modeling of Order Book and Opinion Dynamics (09.3.3-LMT-K-712-02-0026). Dr. A. Kononovičius. 2017–2019.

The idea to apply tools from physics to social systems is not novel, but until 1980s, there were mostly social scientists who took inspiration from physics and not the other way round. The first studies conducted by physicists revealed that social systems exhibit statistical patterns reminiscent of physical systems in critical state. So far, there are no “ideal” models. During the project, we will aim to move towards the “ideal” model. While working on the new models we will take compatibility with theories from social sciences as well as empirical data into account.

International Research Projects

Taiwan-Latvia-Lithuania joint research project: Quantum and Nonlinear Optics with Rydberg-State Atoms (TAP LLT-2/2016) Dr. J. Ruseckas. 2016–2018.

Electromagnetically induced transparency (EIT) involving atomic Rydberg states in a more complicated double tripod level scheme has been investigated. In the double tripod scheme two probe laser fields are propagating inside the atomic medium leading to a two component (spinor) slow light. In the case of non-interacting atoms the propagation of the two-component slow light has been recently demonstrated experimentally. In comparison to previously used schemes for quantum nonlinear optics with Rydberg states, the double tripod scheme can combine spin-orbit coupling for the spinor slow light with an interaction between photons. In a ladder, atom-light coupling configuration the interaction is always attractive independent from the detuning. In contrast, in the proposed scheme the interaction can become repulsive if the one-photon detunings have opposite signs.

Main publication:

Ruseckas, J., Yu, I. A. and Juzeliūnas, G. 2017. Creation of two-photon states via interactions between Rydberg atoms during light storage. Phys. Rev. A 95, 023807.

EU Horizon 2020 Marie Skłodowska-Curie Fellowship: Spin Transport in Interacting Spin-Orbit Coupled Systems. Dr. J. Armaitis. 2016–2018.

We provide a theoretical description of these novel interacting spin-orbit coupled systems. More concretely, we derive equations describing the motion of spin and mass, and solve these equations. We investigate spin transport in the uncharted regime where the inter-particle interactions compete with spin-orbit coupling.

Main publications:

Armaitis, J., Ruseckas, J., Stoof, H. T. C. and Duine, R. A. 2017. Spin Hall mode in a trapped thermal Rashba gas. Phys. Rev. A 96, 053625.

Armaitis, J. and Duine, R. A. 2017. Superfluidity and spin superfluidity in spinor Bose gases. Phys. Rev. A 95, 053607.

Armaitis, J., Ruseckas, J. and Juzeliūnas, G. 2017. Omnidirectional spin Hall Effect in a Weyl spin-orbit-coupled atomic gas. Phys. Rev. A 95, 033635.

Lithuanian Academy of Sciences. Lithuanian Cooperation with CERN. Dr. A. Juodagalvis, since 2008.

Activities at the Compact Muon Solenoid (CMS) experiment at CERN focused on the Drell-Yan process measurement in proton collisions at the center-of-mass energy of 13 TeV recorded in 2015. The measurement is nearly completed; the analysis is entering the collaboration-wide-review (CWR) stage (prior to submission to a journal). Participation in the CMS muon system upgrade project GEM was continued. It focused on GEM construction database development and data integration into CMSSW and the global CMS condition database. DCS shifts in P5 were carried out.

A study of the Grimus-Neufeld model was continued. It is an extended Standard model with one additional Higgs doublet and one heavy right-handed Majorana neutrino. In this model, the light neutrinos acquire masses through the seesaw mechanism coupled to radiative corrections. A presentation at the XLI international conference of theoretical physics “Matter to the Deepest” (Podlesice, Poland, September 3–8, 2017) presented current findings on comparison of the mass values obtained by an exact solution to the values given by the Grimus-Lavoura approximation.

We used applied group-theory to find and classify finite subgroups of U(3) and of SU(3). These group theoretical results can be applied to model-building, specifically to better understand the PMNS (neutrino mixing matrix). 

Main publications:

CMS Collaboration, The Phase-2 Upgrade of the CMS Muon Detectors, Technical design report, CERN-LHCC-2017-012 (12 Sept 2017), 376 pp.

Jurčiukonis, D., Lavoura, L. 2017. Group-theoretical search for rows or columns of the lepton mixing matrix. J.Phys. G 44 no. 4, 045003.

Jurčiukonis, D., Lavoura, L. 2017. GAP listing of the finite subgroups of U(3) of order smaller than 2000. PTEP 2017, no. 5, 053A03.

International programme Gaia-ESO Spectroscopic Survey (ESO project 188.B-3002). Habil. Dr. G. Tautvaišienė. 2012–2018.

We used the Gaia-ESO survey data to characterize the bulge metallicity distribution function (MDF), magnesium abundance, spatial distribution, and correlation of these properties with kinematics. Moreover, the homogeneous sampling of the different Galactic populations provided by the Gaia-ESO survey allowed us to perform a comparison between the bulge, thin disk, and thick disk sequences in the [Mg/Fe] vs. [Fe/H] plane in order to constrain the extent of their eventual chemical similarities. We associate metal-rich stars with the bar boxy/peanut bulge formed as the product of secular evolution of the early thin disk. This is the first time that an analysis of the bulge MDF and α-abundances has been performed in a large area on the basis of a homogeneous, fully spectroscopic analysis of high-resolution data. We also investigated the Mg-Al anti-correlation in Galactic globular clusters and found that it is not seen in all clusters, but disappears for the less massive or most metal-rich clusters. The open cluster Trumpler 23 was investigated in detail. It is a moderately populated, intermediate-age open cluster within the solar circle at a RGC 6 kpc.

Main publications:

Rojas-Arriagada, A., Recio-Blanco, A., de Laverny, P., Mikolaitis, Š., et al. 2017. The Gaia-ESO survey: exploring the complex nature and origins of the galactic bulge populations.Astronomy & Astrophysics, vol. 601, id.A140, 17 p.

Pancino, E., Romano, D., Tang, B., Tautvaišienė, G., et al. 2017. The Gaia-ESO survey: Mg-Al anti-correlation in iDR4 globular clusters. Astronomy & Astrophysics, vol. 601, id.A112, 10 p.

Overbeek, J. C., …Tautvaišienė, G., …Drazdauskas, A., Ženovienė, R., et al. 2017. The Gaia-ESO Survey: the inner disk, intermediate-age open cluster Trumpler 23. Astronomy & Astrophysics, vol. 598, id.A68, 18 p.

Long-term international project: The European Space Agency Satellite Gaia. Prof. V. Straižys, Dr. Habil. G. Tautvaišienė.

We investigated the scientific potential and limitations of the first Gaia Data Release Tycho-Gaia Astrometric Solution (TGAS) component by means of the astrometric data for open clusters. The Gaia DR1 provides the means to examine open clusters far beyond their more easily visible cores, and can provide membership assessments based on proper motions and parallaxes. Parallaxes for 331 classical Cepheids, 31 Type II Cepheids, and 364 RR Lyrae stars in common between Gaia and the Hipparcos and Tycho-2 catalogues are published in Gaia Data Release 1. Good agreement is found from direct comparison of the parallaxes of RR Lyrae stars for which both TGAS and HST measurements are available.

Main publications:

Straižys, V. and Gaia Collaboration. 2017. Gaia Data Release 1. Open cluster astrometry. A&A, 601, A19.

Straižys, V. and Gaia Collaboration. 2017. Gaia Data Release 1. Testing of parallaxes with local cepheids and RR Lyrae stars. A&A, 605, A79.

EC Horizon2020 project: EUROPLANET2020 – Research Infrastructure (project No. 654208). Dr. Habil. G. Tautvaišienė. 2015–2019.

We were working in the work packages dedicated to on-ground observations, coordination and training of amateur astronomers and planeary science outreachers. A summer school was organized on July 18-28, 2017, as part of the Europlanet 2020 RI NA1 (Innovation through Science Networking) Task 5 (Coordination of ground-based observations) and Europlanet 2020 RI NA2 (Impact through outreach and engagement). The aim of the course was to give participants a thorough, multidisciplinary introduction into space missions and the ground-based observations required by space missions before and after launch, as well as an introduction to science communication. More general subjects about specific space missions (Gaia, Kepler, PLATO, TESS), planetary systems, habitability of planets, photometric and spectroscopic techniques were presented. Participants were given some hands-on experience with analysis of stellar chemical composition, detection of stellar variability and/or exoplanets using the Molėtai Astronomical Observatory telescopes (CCD photometry and high-resolution spectroscopy). In addition, the course gave participants the opportunity to develop comprehensive theoretical and practical skills in science communication and engaging with a range of lay audiences, including the public, media, policy makers, schools and educators. 21 participants from 11 countries (Azerbaijan, France, Greece, Italy, Lithuania, Spain, Sweden, Portugal, Romania, Ukraine, and United Kingdom) have been trained.

Main publication:

Scherf, M., Kargl, G., Tautvaisiene, G. and Al-Ubaidi, T. 2017. Europlanet 2020: Fostering the collaboration between professional scientists and amateur astronomers. European Planetary Science Congress http://adsabs.harvard.edu/abs/2017EPSC...11..461S 

Long-term international project The Whole Earth Telescope (WET). Dr. E. Pakštienė, Dr. R. Janulis.

On 24-31 of August (2017) we participated in multi-site campaign for observations of the central pulsating star in the planetary nebulae K1-16, as this object has never been a subject to an extensive multi-site campaign before. The aim of this asteroseismic study was to detect ε-driven pulsations in this star and to measure the evolutionary contraction of the star. We got photometric observational data with the 1.65 m telescope at the Molėtai Astronomical observatory during 6 nights.

Main publication:

Silvotti, R., Schuh, S., Kim, S.-L., Lutz, R., Reed, M., Benatti, S., Janulis, R., Lanteri, L., Ostensen, R., Marsh, T. R., Dhillon, V. S., Paparo, M., and Molnar, L. 2017. The sdB pulsating star V391 Peg and its putative giant planet revisited after 13 years of time-series photometric data. ArXiv e-prints  http://adsabs.harvard.edu/abs/2017arXiv171110942S 

International long-term international project: Kepler Follow-up Program of Kepler Objects of Interest (KFOP-KOIs). Dr. E. Pakštienė, Dr. R. Janulis. Since 2016.

In 2017 we observed two Kepler Objects of Interest: KOI 0880.02 on 30 August and KOI 0759.01 on 31 Aug. The aim of the observations was looking for the Transit Timing Variation and the Transit Duration Variation (TTV/TDV), which are indication of more than one exoplanet in planetary system. Photometric observations were performed at the Moletai Astronomical Observatory with the 1.65 m telescope and Alta U47 CCD camera.

International long-term project: Gaia Science Alerts. Dr. E. Pakštienė, Dr. R. Janulis. Since 2016.

We observed two Gaia Science Alerts objects: gaia17bxh was observed on 30 August, which is a suspected microlensing event, and gaia16aye was observed on 31 August, which is well known as a binary microlensing event discovered in 2016. More observations of gaia16aye were needed to follow the progress of the event. Photometric observations were performed at the Moletai Astronomical Observatory with the 1.65 m telescope and Alta U47 CCD camera.

International project BRITE-Constellation. Dr. E. Pakštienė, Dr. Š. Mikolaitis. Since 2016.

We observed high resolution spectra of the object Eps Persei, which is one of the BRITE-Constellation targets and needs additional spectroscopic observations in order to derive basic characteristics of the star (temperature, surface gravity, chemical composition), to characterize its binary orbit and support space photometry with the time resolved spectroscopy for identification of pulsational modes and study pulsational line profile variations. We obtained several individual high resolution spectra on 22 March, 3 April, 4 April, and 6 April. Also we observed two time series of high resolution spectra. One of them contained 27 individual spectra, which were observed on 7 January, and another one contained 38 individual spectra observed on 8 January. Observations were carried out at the Moletai Astronomical Observatory with the 1.65 m telescope and high resolution eschelle type spectrograph VUES.

National Institutes of Natural Sciences (NINS, Japan) International research project: Construction of Atomic Data and Radiative Transfer Simulations toward Identification of Gravitational Wave Sources and the Origin of Heavy Elements. Prof. Dr. G. Gaigalas. 2016–2018.

We perform atomic structure calculations for r-process elements. We confirm that the opacities from bound-bound transitions of open f-shell, Lanthanide elements are higher than those of the other elements over a wide wavelength range.

COST Action TD1308: Origins and Evolution of Life on Earth and in the Universe (ORIGINS) (http://www.cost.eu/COST_Actions/tdp/TD1308). Action Chair: Prof. Muriel Gargaud, France) (29 countries). Habil. Dr. G. Tautvaišienė. 2014–2018.

In the framework of this COST action, an international conference Early Earth and ExoEarths: Origin and Evolution of Life was organised in Warsaw, Poland on 3–7 April 2017. A scientific presentation “Spectroscopic and Photometric Survey of Northern Sky for Exoplanetary Research” was presented by Mikolaitis Š., Tautvaišienė G., Drazdauskas A., Ženovienė R., Pakštienė E., Janulis R., Bagdonas V., and Klebonas L.

COST Action CA11617: Chemical Elements as Tracers of the Evolution of the Cosmos (ChETEC) (http://www.cost.eu/COST_Actions/ca/ca11617). Action Chair: Dr. Raphael Hirschi, England) (29 countries). Dr. A. Kučinskas, Managing Committee Member, Co-lead of the Working Group 3 (Future Observations). 2017– 2021.

During the first year of this COST action, a strong emphasis was put on the organization and initiation of the action activities. In particular, a join work was started on preparing and submitting new observing proposals, due in 2018, as well as on more extended research programs.

Long-term international project: Researchers’ Night 2016/2017 (LT-2016). I. Balčiūnienė (VU), Dr. A. Kazlauskas (ITPA). 2016–2017.

The main purpose of this project is meetings of scientists with public. Such meetings took place on the September 29^th at the Molėtai Astronomical Observatory and Planetarium of the Institute of Theoretical Physics and Astronomy. It is a Europe-wide public event dedicated to popular science. More than 30 countries and over 300 cities are involved. The Moletai Astronomical Observatory programme included the show “Hinc itur ad astra”, given by the Vilnius University theatre drama troupe Minimum (director R. Venckus), 12 lectures given by eight lecturers, tours to professional telescopes, stargazing, show of physical experiments. The especially notable event was the online video-tour of CERN and discussion with scientists working there. Almost all the staff of the Observatory and several scientists from other departments met with 400 people visiting the Observatory.

MAIN R&D&I (RESEARCH, DEVELOPMENT AND INNOVATION) PARTNERS

Aarhus University (Denmark)
Nicolaus Copernicus Astronomical Centre (Poland)
Kiepenheuer Institut fur Sonnenphysik (Germany)
Leibniz-Institut fuer Astrophysik Potsdam (Germany)
Landessternwarte – Zentrum für Astronomie der Universität Heidelberg (Germany)
Observatoire de Paris, CNRS, Université Paris Diderot (France)
Institute of Theoretical Astrophysics, University of Oslo (Norway)
Center for Physical Sciences and Technology (Lithuania)
Main Astronomical Observatory of Academy of Sciences (Ukraine)
National Astronomical Observatory (Japan)
University of Latvia (Latvia)
Vatican Observatory (USA)
Washington University (USA)
Valparaiso University (USA)
Yale University (USA)
National Institute of Standards and Technology (USA)
University of Kentucky, Lexington (USA)
National Institute for Fusion Science (Japan)
Materials Science and Applied Mathematics, Malmö University, Malmö (Sweden)
Chimie Quantique et Photophysique, Université Libre de Bruxelles (Belgium)
Cracow Jagiellonian University (Poland)
University of South Carolina (USA)
Queen’s University Brelfast (UK)
Nuclear Physics Center at Lisbon University (Portugal)
Istituto Nazionale Fisica Nuclear, Pisa (Italy)
Institute for Theoretical Physics II, Ruhr University Bochum (Germany)
University of Seville, Seville (Spain)
Ohio University, Athens, Ohio (USA)
National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing (USA)
Triangle Universities Nuclear Laboratory, Durham, North Carolina (USA)
Jagiellonian University, Cracow (Poland)
University of Nebraska-Lincoln, Lincoln, Nebraska (USA)
Seoul National University, Seoul (Korea)
European Organization for Nuclear Research CERN (Switzerland)
Joint Institute for Nuclear Research (Dubna, Russia)
Centre for Theoretical Particle Physics, University of Lisbon, CFTP (Portugal)
National Institute of Standards and Technology (USA)
National Tsing Hua University (Taiwan)
Heriot-Watt University (UK)
ICREA and ICFO (Spain)
Leibniz Universität, Hannover (Germany)
Boston University (USA)

OTHER SCIENTIFIC ACTIVITIES

Dr. K. Černis –

• member of the Lithuanian Astronomical Olympiad Council;
• member of the International Astronomical Union (IAU).

Prof. G. Gaigalas, Dr. P. Rynkun, and L. Radžiūtė –

• member of CompAS (The International collaboration on Computational Atomic Structure) group, http://ddwap.mah.se/tsjoek/compas/.

Dr. V.  Gontis –

• member of the association of Euroscience, http://www.euroscience.org/.

Dr. A. Juodagalvis –

• contact person for the CMS outreach and communication in Lithuania, representing the Lithuanian Team at CERN CMS experiment;
• chairman of the Committee to Coordinate Vilnius University Collaboration with CERN.

 Habil. Dr. G. Juzeliūnas –

• associated member of the National Center for Theoretical Sciences at the National Tsing Hua University (Taiwan);
• member of the Institute of Physics (UK);
• co-chair of the scientific organizing committee of the 42^nd National Physics Conference, Vilnius, Lithuania, October 4–16, 2017.

Prof. B. Kaulakys –

• member of the Institute of Physics (UK);
• member of the European Physical Society;
• editorial board member of the Lithuanian Journal of Physics;
• editorial board member of the journal Nonlinear Analysis. Modeling and Control;
• vice-president of the Lithuanian Association of Nonlinear Analysts;
• council member of the Lithuanian Scientific Society;
• member of the Senate of Vilnius University.

Prof. R. Karazija –

• editorial board member of the Lithuanian Journal of Physics;
• member of the Lithuanian Academy of Sciences.

Dr. A. Kynienė –

• president of the Vilnius City Board of the Physics Teachers’ Association;
• member of Vilnius City Physics Methodical Board;
• Team leader of Particle Physics Outreach Group at the VU Experimental Nuclear and Particle Physics Centre.

Dr. A. Kučinskas –

• member of the Board of Directors of the international journal Astronomy and Astrophysics;
• vicepresident of the Lithuanian Astronomical Society;
• member of the International Astronomical Union.

Dr. A. Kupliauskienė –

• head of the board of Association “BASNET Forumas”, http://www.basnetforumas.eu /index.php?option=com_content&view=frontpage&lang=en);
• a substitude member of Lithuania in the board of European Platform of Women Scientists (EPWS).

Dr. Š. Mikolaitis, Dr. D. Narbutis, Dr. E. Pakštienė, Dr. J. Sperauskas, Dr. R. Stonkutė –

• members of the International Astronomical Union (IAU).

Prof. V. Straižys –

• editor-in-chief of the International journal Baltic Astronomy;
• member emeritus of the Lithuanian Academy of Sciences;
• member of the working group on stellar classification of the ESA Gaia project;
• member of the International Astronomical Union;
• member of the European Astronomical Society.

Dr. J. Tamulienė –

• management committee member of the Lithuanian Physics Society.

Habil. Dr. G. Tautvaišienė –

• vicepresident of the International Union of Pure and Applied Physics;
• vicepresident of the Lithuanian Physics Society;
• chair of Astrophysics Commission at the International Union of Pure and Applied Physics;
• member of the International Astronomical Union (IAU);
• founding member of the European Astronomical Society;
• editorial board member of the journal Baltic Astronomy;
• editor-in-chief of the annual astronomical almanac Lietuvos dangus (Sky of Lithuania);
• scientific organizing committee member of the international conference XXIX Texas Symposium on Relativistic Astrophysics, December 3–8, 2017, Cape Town, South Africa;
• scientific organizing committee member of the international conference Early Earth and ExoEarths: Origin and Evolution of Life, Warsaw, Poland, 3–7 April, 2017;
• local organizing committee member of the of the European Planetary Science Congress 2017, Riga, Latvia, 17–22 September, 2017;
• Co-Chair of the scientific organizing committee of the 42^nd National Physics Conference, Vilnius, Lithuania, October 4–16, 2017;
• scientific organizing committee member of the of the international conference Baltic Applied Astroinformatics and Space Data Processing, August 23–24, 2017, Ventspils, Latvia;
• Chair of the scientific organizing committee of the international Europlanet Summer School Space Missions: Ground-based Observations and Science Communication, July 18–28, 2017, Molėtai, Lithuania.

Prof. Dr. V. Vansevičius –

• member of the International Astronomical Union (IAU).