Faculty of Physics

Sukurta: 26 June 2017

9 Saulėtekio, LT-10222 Vilnius
Tel. 236 6001, fax 236 6003
E-mail:
http://www.ff.vu.lt

Dean – Prof. Habil. Dr. Vytautas Balevičius

STAFF

68 teachers (incl. 63 holding research degree), 49 research fellows (incl. 37 holding research degree), 83 doctoral students.

Astronomical Observatory
Department of General Physics and Spectroscopy
Department of Quantum Electronics
Department of Radiophysics
Department of Semiconductor Physics
Department of Solid State Electronics
Department of Theoretical Physics

RESEARCH AREAS

Solid State Physics and Technology

Spectrometric Characterization of Materials and Electronic/Molecular Processes

Laser Physics and Technology

DOCTORAL DISSERTATIONS MAINTAINED IN 2016

A. Alesenkov. Micromachining of nontransparent materials in air and water with femtosecond laser pulses.

J. Jurkevičius. Photoluminescence efficiency in wide-band-gap III-nitride semiconductors and their heterostructures.

B. Lenkevičiūtė-Vasiliauskienė. Organic light emitting diodes: the investigation of new materials and structures towards broad emission spectra.

J. Pavlov. Detector structures on defect-rich silicon and wide band-gap semiconductors.

M. Pučetaitė. Vibrational spectroscopy and microspectroscopic imaging of urinary stones and biological fluids.

K. Redeckas. Electronic kinetics and structural dynamics of photochromic and photosynhetic pigments.

I. Reklaitis. Advanced III-nitride-based optoelectronic devices: fabrication and characterization.

S. Rekštytė. The development and applications of the methods of direct laser writing using femtosecond light pulses in transparent cross-linkable materials.

V. Rumbauskas. Peculiarities of carrier scattering and thermal emission in large fluence irradiated silicon.

T. Stanislauskas. High power ultrashort CEP stable pulses VIA optical parametric amplification.

M. Stephen. Charge transport and novel poly(fullerene)s in organic photovoltaics.

K. Steponkevičius. Third harmonic generation and six-wave mixing of femtosecond laser pulses in air.

V. Voiciuk. Photophysical transformations in molecules studied by ultrafast multi-pulse spectroscopy.

CONFERENCES ORGANIZED IN 2016

4^th Lithuanian – Polish – Ukrainian Meeting on Ferroelectricity

MAIN SCIENTIFIC ACHIEVEMENTS IN 2016

Best oral presentation Award in SPIE Laser Damage 2015 (Boulder, Colorado, United States) - What time-resolved measurements tell us about femtosecond laser damage?

New spectroscopic approach for in situ determination of cancerous biological tissues areas was developed.

New microwave spectroscopy techniques, designed to characterize crystals, ceramics, powders and liquids, were developed.

ASTRONOMICAL OBSERVATORY

29 M. K. Čiurlionio, LT-03100, Vilnius
Tel. 239 8760, fax 239 8767
E-mail:

Head – Prof. Dr. Vladas Vansevičius

STAFF

Professors: Prof. Dr. V. Vansevičius, Dr. A. Kučinskas.
Associate professors: Dr. A. Bridžius, Dr. D. Narbutis, Dr. R. Stonkutė, Dr. K. Zubovas.
Senior research fellow: Dr. J. Sperauskas.
Junior research fellows: V. Deveikis, S. Raudeliūnas.
Doctoral student: J. Bialopetravičius.

RESEARCH INTERESTS

Structure and evolution of galaxies
Star clusters and binary stars
Stellar photospheres

RESEARCH PROJECTS CARRIED OUT IN 2016

Projects Supported by University Budget

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

A detailed study of the Leo A galaxy was carried out using ground (Subaru, National Astronomical Observatory of Japan) and space based observations (Hubble Space Telescope) from near-ultraviolet to near-infrared. Integral parameters and recent (during the last billion years) star formation history of this remarkable dwarf irregular galaxy were determined.

An analysis of 1049 K-M dwarfs in the solar vicinity was performed based on the long term (2000-2015) observations of radial velocities with Coravel type spectrometer at the Molėtai Astronomical Observatory of the Vilnius University and the Steward Observatory of the Arizona University. It was determined that only ~3 % of K-M stars in solar vicinity belong to the thick disk population.

It was proved that 9 CH-like stars out of 12 monitored are spectroscopic binaries and their chemical peculiarity, determined from high resolution (R=45000) spectra, can arise due to mass exchange between components.

First determination of 3D LTE oxygen abundance in the metal-poor halo giant HD 122563 using a 3D hydro-dynamical CO⁵BOLD model atmosphere and spectral lines of OH molecule located in the UV part of the spectrum was performed. Using OH UV lines, we determined a 3D LTE oxygen abundance of A(O)3D LTE=6.23±0.13 ([O/Fe]=0.07±0.13). This is in fair agreement with the oxygen abundance obtained from OH IR lines, A(O)3D LTE=6.39±0.11 ([O/Fe]=0.23±0.11), however, it is lower than that determined when using the forbidden [O I] line, A(O)3D LTE=6.53±0.15 ([O/Fe]=0.37±0.15).

Main publications:

Začs, L., Musaev, F., Kaminsky, B., Pavlenko, Ya., Grankina, A., Sperauskas, J., Hrivnak, B. 2016. Spectroscopic variability of IRAS 22272+5435. Astrophysical Journal, 816:3.

Sperauskas, J., Začs, L., Schuster, W.J., Deveikis, V. 2016. The binary nature of CH-like stars. Astrophysical Journal, 826:85.

Sperauskas, J., Bartašiūtė, S., Boyle, R. P., Deveikis, V., Raudeliūnas, S., Apgren, A. R. 2016. Radial velocities of K-M dwarfs and local stellar kinematics. Astronomy and Astrophysics, 596, A116.

Prakapavičius, D., Kučinskas, A., Dobrovolskas, V., Klevas, J., Steffen, M., Bonifacio, P., Ludwig, H.-G., Spite, M. 2016. 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 and Astrophysics, doi: http://dx.doi.org/10.1051/0004-6361/201629306.

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

Centre for Physical Sciences and Technology (Lithuania)
Main Astronomical Observatory of Academy of Sciences of Ukraine

National Astronomical Observatory of Japan
University of Latvia
Valparaiso University (USA)
Vatican Observatory (USA)
Yale University (USA)

OTHER SCIENTIFIC ACTIVITIES

Prof. Dr. V. Vansevičius, Dr. A. Kučinskas, Dr. D. Narbutis, Dr. J. Sperauskas, Dr. R. Stonkutė –

members of the International Astronomical Union.

DEPARTMENT OF GENERAL PHYSICS AND SPECTROSCOPY

3 Saulėtekio, LT-10257 Vilnius
Tel. 236 6040, fax 236 6003
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. A. Gruodis, Dr. A. Maršalka, Dr. F. Kuliešius, Dr. J. Čeponkus, Dr. V. Urbonienė, Dr. L. Juodis.

Lecturers: Dr. K. Aidas, V. Klimavičius, M. Pučetaitė, M. Velička, D. Lengvinaitė.
Doctoral students: N. Karalius, J. Kausteklis, N. Kelminskienė, V. Klimavičius, K. Kristinaitytė, J. Lach, S. Tamošaitytė, M. Pučetaitė, M. Velička, D. Lengvinaitė.

RESEARCH INTERESTS

Spectroscopy of atoms, molecules and condensed matter
IR, UV, Raman, NMR investigation of organic compounds of the organized structures in the liquid, solid phases and nano-crystals
Phase transitions and critical phenomena
Molecular interactions, hydrogen bonding, conformational analysis
Spectral markers in biological tissues and fluids
Matrix isolation FTIR spectroscopy

MAIN SCIENTIFIC ACHIEVEMENTS IN 2016

New spectroscopic approach for in situ determination of cancerous biological tissues areas was developed.

New NMR methods based on CP kinetics analysis for studies of fine structure of nanostructured materials were developed and tested on nanostructured calcium hydroxyapatites.

RESEARCH PROJECTS CARRIED OUT IN 2016

Projects 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. 2016.

New NMR methods based on CP kinetics analysis for studies of fine structure of nanostructured materials were developed and tested on nanostructured calcium hydroxyapatites. Optical fiber based ATR FTIR sensor for qualitative and quantitative analysis of molecular solids and fluids was developed, constructed and tested on biological samples.

Main publications:

Pucetaite, M., Velicka, M., Pilipavicius, J., Beganskiene, A., Ceponkus, J., Sablinskas, V. 2016. Uric acid detection by means of SERS spectroscopy on dried Ag colloidal drops. Journal of Raman Spectrocopy, vol. 47(6), p. 681–686.

G. Steiner, G. Preusse, C. Zimmerer, M. Krautwald-Junghanns, V. Sablinskas, H. Fuhrmann, E. Koch, T. Bartels. 2016. Label free molecular sexing of monomorphic birds using infrared spectroscopic imaging. Talanta, vol. 150, p. 155–161.

Klimavicius, V., Dagys, L., Balevicius, V. 2016. Subnanoscale order and spin diffusion in complex solids through the processing of cross-polarization kinetics. J. Phys. Chem. C, vol. 120, p. 3542–3549.

Kristinaitytė, K., Dagys, L., Kausteklis, J., Klimavicius, V., Doroshenko, I., Pogorelov, V., Valevičienė, N. R., Balevicius, V. 2016. NMR and FTIR studies of clustering of water molecules: from low-temperature matrices to nano-structured materials used in innovative medicine. Journal of Molecular Liquids http://dx.doi.org/10.1016/j.molliq.2016.11.076

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.

New spectroscopic method of 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 prepared and submitted.

International Research Projects

Research Council of Lithuania. Lithuanian - French project: Study of Molecules with Internal Hydrogen Bond Isolated in Cryogenic Matrices (financed by project number TAP LZ1/2015). Assoc. Prof. J. Čeponkus. 2015–2016.

Studies of Acetylacetone molecule isomerization and interaction with water molecules were performed by the means of matrix isolation vibrational spectroscopy. Novel technique involving matrix isolation technique and Raman scattering spectroscopy was used to study of the title compounds.

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.

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

Networking project: “HOPE” (Nr. 540130-LLP -1.2013-1-FR-ERASMUS-ENV 2013-34710/001-001). Dr. G. Dikčius.

Analysis of possible means of integration of scientific and technological aspects in teaching of physics was performed.

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.

Service agreement. ²⁹Si NMR MAS measurements and analysis of silica gels. (Nr.15/36 PPA2016-05-05). V. Klimavičius. 2016.

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;
Chairman of graduate studies committee Applied Physics at Vilnius University.

Prof. V. Balevičius –

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

Dr. G. Dikčius –

institutional ERASMUS coordinator for Physics;
Vilnius University representative member for HOPE thematic network.

DEPARTMENT OF QUANTUM ELECTRONICS

10 Saulėtekio, LT-10223 Vilnius
Tel.: 236 60 50, 236 60 05
E-mail:

Head - Prof. Habil. Dr. Valdas Sirutkaitis

STAFF

Professors: Habil. Dr. V. Sirutkaitis, Habil. Dr. R. Rotomskis, Habil. Dr. V. Smilgevičius, Dr. R. Gadonas, Dr. G. Streckytė, Dr. A. Dubietis, Dr. G. Valiulis, Dr. S. Bagdonas, Dr. M. Vengris, Habil. Dr. A. Piskarskas (emeritus), Habil. Dr. Emeritus A. Stabinis.

Leading researchers: Dr. A. Varanavičius, Dr. V. Vaičaitis.

Associate professors: Dr. O. Balachninaitė, Dr. A. Matijošius, Dr. V. Karenauskaitė, Dr. V. Jarutis, Dr. A. Melninkaitis, Dr. V. Tamulienė, Dr. V. Kudriašov, Dr. D. Paipulas, Dr. R. Butkus, Dr. G. Tamošauskas, Dr. A. Čiuplys (part-time), Dr. M.Barkauskas (part-time).

Senior research fellows: Dr. E. Gaižauskas, Dr. R. Grigonis, Dr. M. Malinauskas.

Research fellows: Dr. D. Kaškelytė, Dr. M. Peckus.

Lecturers: J. Jurkienė, Dr. R. Piskarskas.

Head of the teaching laboratory: A. Čiburys.

Doctoral students: A. Baškevičius, T. Kudrius, M. Matulionytė, S. Rekštytė , K. Redeckas, K. Stankevičiūtė (until October 2016), K. Steponkevičius (until October 2016), L. Mažulė, K. Michailovas, I. Pipinytė, P. Stanislovaitis, J. Vengelis, R. Budriūnas, S. Butkus, N. Garejev, D. Gailevičius, I. Stasevičius, M. Ivanov, T. Tičkūnas, L. Jonušauskas, R.Šuminas, L.Smalakys, P.Grigas.

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

MAIN SCIENTIFIC ACHIEVEMENTS IN 2016

Best Oral Presentation Award in SPIE Laser Damage 2015 (Boulder, Colorado, United States) - What time-resolved measurements tell us about femtosecond laser damage? [9632-23] Andrius Melninkaitis, Nerijus Šaulys, Linas Smalakys, Balys Momgaudis, Julius Vaicenavičius, Simona Barkauskaite, Valdas Sirutkaitis, Vilnius Univ. (Lithuania); Laurent Gallais, Aix Marseille Univ., Institut Fresnel (France); Stephane Guizard, Ecole Polytechnique (France).

Malinauskas, M., Žukauskas, A., Hasegawa, S,. Hayasaki, Y., Mizeikis, V., Buividas, R., Juodkazis, S. 2016. Ultrafast laser processing of materials: from science to industry. Light: Science & Applications, Nature publishing group 5, e16133; doi:10.1038/lsa.2016.133 [IF - 13.757].

Zukauskas, A., Malinauskas, M., Seniutinas, G., Juodkazis, S. 2016. Rapid laser optical-printing in 3D at a nanoscale, in Multiphoton lithography, Wiley, 10.1002/9783527682676.ch1.

RESEARCH PROJECTS CARRIED OUT IN 2016

Projects Supported By University Budget

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

Ultrabroadband supercontinuum enhanced by third, fifth and seventh laser harmonics and spanning from the ultraviolet to the mid infrared was demonstrated in CaF₂ crystal.

Optical parametric amplification in the trapping regime was investigated theoretically and numerically. Improvement of the coherence in both amplified waves – signal and idler – was demonstrated. Wide region of the wavelengths can be reached in this way in contrast to the traditional group velocity matching method.

Noncollinear optical parametric amplification was further rstudied. The possibilities to reduce influence of amplified parametric fluorescence (APF) were revealed. APF suppression due to the presence of a seed pulse in the OPA was found to be by order of magnitude compared to typical OPA operating conditions when pump-to-signal conversion efficiency is about 10 percents. The numerical results were compared with the experimental ones.

The laser-induced damage threshold values in uncoated periodically poled lithium niobate (MgO:PPLN) samples at different pulse repetition rates of femtosecond Yb:KGW laser were calculated. The results were compared with the experimental ones. The influence of the temperature diffusion in the sample was studied. Publication is in progress.

Optical parametric amplification of coherent signal by incoherent conical pump beam was studied. The amplified signal beam remains narrowband and the generated idler conical beam is incoherent.

Possibility of temporal characterization of femtosecond laser pulses by recording their fifth-order intensity autocorreliations via noncollinear six-wave mixing in air has been demonstrated.

It was shown that the contrast of the pulses produced in a high-gain BBO-based femtosecond noncollinear optical parametric amplifier essentially depends on the chosen interaction geometry and can be improved by ~ 2 orders of magnitude.

Main publications:

Garejev, N. Jukna, V. Tamošauskas, G. Veličkė, M. Šuminas, R. Couairon, A. Dubietis, A. 2016. Odd harmonics-enhanced supercontinuum in bulk solid-state dielectric medium. Optics Express, vol. 24, p. 17060–17068.

Gaižauskas, E., Steponkevičius, K., Vaičaitis, V. 2016. Fifth-order intensity autocorrelations based on six-wave mixing of femtosecond laser pulses. Phys. Rev. A, vol. 93 (2), Art. No. 023813.

Tamuliene, V., Stanislovaitis, P. 2016. Optical parametric amplification by incoherent pump in the trapping regime. JOSA B, vol. 33, p. 720–724, http://dx.doi.org/10.1364/JOSAB.33.000720.

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

Femtosecond Stimulated Raman Spectroscopy was successfully applied for the investigation of ultrafast structural dynamics in carotenoids and photochromic pigments.

Laser (nano) polymerization via efficient thermal and linear processes was systematically studied to meet the needs of material processing at the practically applicable scale. The revealed mechanisms determining the spatial resolution of the polymerized features and increase in fabrication throughput were deduced.

Accumulation of carboxylated polyethylene glycol (PEG) CdSe/ZnSquantum dots (QDs) has been monitored in living fibroblasts using confocal microscopy and fluorescence-lifetime imaging (FLIM). The varying photoluminescence lifetime was observed for the intracellular QDs in different intracellular microenvironment. It revealed structural heterogeneity of endosomes and enabled the distinguishing between endosomes of different maturity.

Photostability of bovine serum albumin stabilized gold nanoclusters (BSA-Au nanoclusters) have been studied. Two photoluminescence bands possessing different behaviour upon irradiation were found. BSA-Au nanoclusters exhibit hifh colloidal stability when heated up to 65 degrees.

Main publications:

Žukauskas, A., Malinauskas, M., Seniutinas, G., Juodkazis, S. 2016. Rapid laser optical-printing in 3D at a nanoscale. Multiphoton Lithography, Wiley, doi: 10.1002/9783527682676.ch1.

Damalakiene, L., Karabanovas, V., Bagdonas S., Rotomskis, R. 2016. Fluorescence-lifetime imaging microscopy for visualization of quantum dots’ endocytic pathway. International Journal of Molecular Sciences, vol. 17(4), p. 473.

Poderys, V., Matulionyte-Safine, M., Rupsys, D., Rotomskis, R. 2016. Protein stabilized Au nanoclusters: spectral properties and photostability. Lithuanian Journal of Physics, vol. 56(1), p. 55–65.

National Research Projects

Research Council of Lithuania. High Average Power <10 Fs Pulse Formation by Parametric Chirped Pulse Amplification Method (ČIPS) (No. MIP-056/2014). Dr. A.Varanavičius. 2014–2016.

A generation of >4 TW peak power pulses at 1 kHz repetition rate by OPCPA system pumped by tandem fs Yb: KGW and ps Nd:YAG lasers has been demonstrated. Employing passively CEP stabilized Yb:KGW based frontend and high energy pump from diode pumped Nd:YAG laser amplifiers, a compact grism and an AOPDF based pulse stretcher we have obtained high spatio-temporal quality output pulses with the energy of up to 50 mJ which were compressed down to sub 9 fs. CEP noise was reduced down to 250 mrad by controlling delay of acoustic wave in AOPDF. It was shown that seed pulse pre-amplified by femtosecond pulses enables to get temporal contrast as high as 10¹⁰at 10 ps before the main pulse.

Research Council of Lithuania. Spatial Filters Based on Photonic Crystals for Improvement of Spatial Structure of Laser Beams (No. MIP-056/2014). Dr. M. Peckus. 2014–2016.

Photonic crystals for spatial filtering and for improving spatial quality of light beams are fabricated and investigated. It was demonstrated that specially designed photonic crystal in the cavity of a microchip laser, can significantly improve the beam quality. Experiments show that a microchip laser, due to spatial filtering functionality of intracavity photonic crystal, improves the beam quality factor M2 reducing it by a factor of 2, and increase the brightness of radiation by a factor of 3.

Main publication:

Gailevicius, D., Koliadenko, V., Purlys, V., Peckus, M., Taranenko, V., Staliunas, K. 2016. Photonic crystal microchip laser. Scientific Reports, vol. 6, 34173.

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 and sizes were fabricated using direct laser writing in pre-polymers technique. Constructs with hexagonal and rectangular shaped pores were seeded with allogenetic rabbit chondrocytes to investigate the influence of pore shape to cell proliferation. Preliminary results show that scaffolds with hexagonal pore shape perform better. Also investigation of photo-initiator influence to the scaffold’s biocompatibility is under way.

Main publication:

Mačiulaitis, J., Rekštytė, S., Ūsas, A., Jankauskaitė, V., Gudas, R., Malinauskas, M., Mačiulaitis, R. 2016. Characterization of tissue engineered cartilage products: Recent developments in advanced therapy. Pharmacol. Res., vol. 113 (Part B), p. 823–832.

Research Council of Lithuania. R&D Project: Two Channel Tunable Parametric Oscillator for Multiphoton Polymerization Technology: Test Application of Model and Prototype Creation (OPO4DLW) (No. TEC-05/2015). Prof. R. Gadonas. 2015–2016.

The laboratory version of two independent channel optical parametric oscillators developed by Light Conversion Company was tested in direct laser writing experiments. The dependence of polymerisation and optical damage thresholds was measured in both sensitized and unsensitised photoresist material. The test data were used in development of OPO prototype which was completed at “Light conversion” company. Materials for publication have been prepared. The data are accepted for presentation at international conference CLEO-2017.

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, in the regimes of normal and anomalous group velocity dispersion, demonstrating the universality of the proposed approach over a wide wavelength range.

Main publication:

Šuminas, R., Tamošauskas, G., Valiulis, G., Dubietis, A. 2016. Spatiotemporal light bullets and supercontinuum generation in b-BBO crystal with competing quadratic and cubic nonlinearities. Optics Letters vol. 41, p. 2097–2100.

International Research Project

Horizon 2020 Project Integrated European Laser Laboratories IV (LASERLAB-Europe IV). 2015–2019.

LASERLAB-EUROPE IV comprises 33 of the leading European laser infrastructures and, together with subcontractors and associate partners, involve coordinated activities in 21 countries. The Vilnius University represented by Department of Quantum Electronics and Laser Research Centre is member of LASERLAB-EUROPE IV and is involved in two joint research activities (JRA), networking and provide transnational access.

Within JRA Innovative Laser Technologies (ILAT), spatial, frequency and energy properties of terahertz radiation excited by focused tunable in wavelength femtosecond laser pulses in air were analyzed both theoretically and experimentally. Extremely broadband (spectral bandwidth of up to 60 THz) spectra of generated THz pulses have been registered. The second task performed within JRA ILAT was related to some aspects of laser-induced damage investigation using digital holography.

Within JRA Biomedical Optics for Life Science Applications (BIOAPP), the resistance of polymer microlenses to GW intensities was systematically studied and components made of non-photosensitised resists showed significantly better performance. The second task performed within JRA BIOAPP was related with the application of LIBS in monitoring the micromachining of biocompatible soda-lime glass immersed in water with femtosecond high repetition rate pulses.

Within Transnational Access program, three research projects together with researchers from Greece, Germany and France were performed.

Main publication:

Baskevicius, A., Balachninaite, O., Karpavicius, M., Butkus, S., Paipulas, D., Sirutkaitis, V. 2016. Monitoring of the femtosecond laser micromachining process of materials immersed in water by use of laser-induced breakdown spectroscopy. JLMN-Journal of Laser Micro/Nanoengineering, vol. 11, p. 381–387.

Institutional partnership project: Investigating Optomechanical Properties of Hybrid Polymer-Glass Devices Made using Femtosecond Laser Processing implemented under the project of the programme Research and Development within the framework of the Lithuanian-Swiss cooperation programme to reduce economic and social disparities within the enlarged European Union (No CH-3-ŠMM-02/05). Project leaders: Prof. V. Sirutkaitis (Lithuania), Prof. Y. Bellouard (Swiss). 2016.

The objective of the project was to develop and investigate novel miniature hybrid photonic elements fabricated out of polymer and glass by combining three different approaches of material modification using femtosecond laser pulses: modification of glass, precision cutting of glass via laser assisted chemical etching and two-photon polymerization. Sensor design was carried out by the EPFL GALATEA group (lead by prof. Y.Bellouard). Meanwhile, researchers at the University of Vilnius applied the femtosecond two-photon polymerization technique. Secondments of the PhD students and other researchers had to examine the possibility to combine the three mentioned femtosecond laser microfabrication methods for the creation of the sensor as well as strengthen the groups’ scientific potential and create conditions for further cooperation.

Lithuanian-French cooperation programme Gilibert project: Singular Optical Fibers: Fabrication and Application for the Control of Optical Angular Momentum at a Microscale (Grant No. TAP LZ-4/2015). Dr. M. Malinauskas. 2015–2016.

Main publication:

Balcytis, A., Hakobyan, D., Gabalis, M., Zukauskas, A., Urbonas, D., Malinauskas, M., Petruskevicius, R., Brasselet, E., Juodkazis, S. 2016. Hybrid curved nano-structured micro-optical elements. Opt. Express, vol. 24 (15), p. 16988–16998.

Lithuanian-French cooperation programme Gilibert project: Flights: Femtosecond Light in Transparent Solids (Grant No. TAP LZ-3/2015). Project leaders S. Guizard (France) and A. Melninkaitis (Lithuania). 2015–2016.

The key objective of this project was to carry out coordinated transfer of knowledge between Lithuanian and French teams with aim to develop new of scientific excellence in the field of ultrafast laser-mater interactions. The main performed experiments were directed to full characterization of the interaction of ultrashort pulses under experimental conditions relevant for laser machining in the bulk of dielectric materials: a) determination of the energy deposition map, b) characterization of the beam propagation; c) determination of the final state: long lived plasma or solid with a certain density of defects.

NATO Science for Peace and Security programme (Vilnius University + Universitat Politecnica de Catalunya + Shizuoka University + Swinburne University of Technology + University of Economics and Technology) project: Nanostructures for Higly Efficient Infrared Detection. Dr. M. Malinauskas, 2016–2019.

Project info [https://www.researchgate.net/project/Nanostructures-for-Highly-Efficient-Infrared-Detection].

Main publications:

Rekstyte, S., Jonavicius, T., Gailevicius, D., Malinauskas, M., Mizeikis, V., Gamaly, E. G., Juodkazis, S. 2016. Nanoscale precision of 3D polymerization via polarization control. Adv. Opt. Mater., vol. 4(8), p. 1209–1214. 10.1002/adom.201600155, Wiley-VCH Verlag GmbH & Co.

Sanchez-Padilla, B., Zukauskas, A., Aleksanyan, A., Balcytis, A., Malinauskas, M., Juodkazis, S., Brasselet, E. 2016. Wrinkled axicons: shaping light from cusps. Opt. Express, vol. 24(21), p. 24075–24082.

Mutual Funds Taiwan – Latvia – Lithuania project: Mesenchymal Stem Cell and Cancer Stem-Like Cell Response to Nanoparticle Treatment (Grant No. TAP LLT 03/2014). Prof. R. Rotomskis. 2014–2016.

The goal of this project is to evaluate the response of mesenchymal stem cells and cancer stem-like cells to the nanoparticle and quantum dot treatment. During the project activities the uptake and distribution of negatively charged superparamagnetic iron oxide (Fe3O4) nanoparticles (SPIONs) in mouse embryonic fibroblasts NIH3T3, and magnetic resonance imaging (MRI) signal influenced by SPIONs injected into experimental animals, were visualized and investigated.

Main publication:

Jarockyte, G., Daugelaite, E., Stašys, M., Statkute, U., Poderys, U., Tseng, V.T-C., Hsu, S-H., Karabanovas, V., Rotomskis, R. 2016. Accumulation and toxicity of superparamagnetic iron oxide nanoparticles in cells and experimental animals. International Journal of Molecular Sciences, vol. 17(8), UNSP 1193.

Contractual Research

Study of Kerr effect in transparent materials–Grant with Crystal Laser SA (France). 2015–2016.

Fabrication of various micro-structures out of different pre-polymers (SZ2080, OrmoComp, SU-8, PETA) by employing femtosecond laser lithography, Customer - Altechna R&D, 2016.

Fabrication of 2D pillars out of biocompatible OrmoComp pre-polymer to be used for investigating the role of structure geometry on cellular adhesion using a parallel plate flow chamber, Customer: Riga Technical University Institute for Biomedicine and Nanoengineering.2016.

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

Svinburne University of Technology, Centre for Micro-Photonics (H34) (Australia).

UPC (Universitat Politechnica de Catalunya), Departament de Fisica i Enginyeria Nuclear, Colom (Spain)

Institut Fresnel-CNRS UMR 7249-Equipe ILM, Escole Centrale Marseille-Aix Marseille Universite (France)

Laboratoire des Solides Irradiés, Ecole Polytechnique (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 (Greece)

Centre de Physique Théorique, CNRS, Ecole Polytechnique, Université Paris-Saclay, Palaiseau (France)

OTHER SCIENTIFIC ACTIVITIES

Prof. V. Sirutkaitis –

member of international Program Committee of the 5^th Pacific-rim Laser Damage Conference PLD’16, Pacifico Yokohama, Yokohama, Japan, 18–20 May, 2016, http://www.ile.osaka-u.ac.jp/PLD-16/files/Call-for-Papers-PLD16_rev2.pdf.

Dr. M. Malinauskas –

associate editor of Optics Express (OSA).

DEPARTMENT OF RADIOPHYSICS

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. T. Šalkus, Dr. E. Kazakevičius, Dr. S. Pralgauskaitė, Dr. V. Jonkus, Dr. M. Ivanov, Dr. R. Rimeika, Dr. M. Žilinskas, Dr. R. Sobiestijanskas.

Lectures: Dr. K. Svirskas, Dr. R. Aleksiejūnas, Dr. Č. Pavasaris, Dr. R. Giriūnienė, E. Palaimienė, Š. Svirskas, M. Šimėnas, K. Ikamas, Dž. Jablonskas.

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.

Engineering staff: A. Sereika, V. Adomaitis, Dr. Č. Pavasaris, A. Cesiul, J. Glemža.

Doctoral students: E. Palaimienė, R. Mackevičiūtė, J. Aleksandravičius, J. Zdanevičius, J. Belovickis, J. Krivochiža, Š. Svirskas, Dž. Jablonskas, I. Kranauskaitė, M. Šimėnas, K. Ikamas, A. Plyushch, I. Zamaraitė, D. Petrulionis, S. Daugėla, J. Glemža, S. Balčiūnas, D. Adamchuk.

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.

Technological processing of solid electrolyte ceramics.Broadband impedance spectroscopy of oxygen and lithium conducting solid electrolytes

RESEARCH PROJECTS CARRIED OUT IN 2016

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.

Noise Characteristics Investigation of Quantum Structure Devices Employed in Telecommunication Systems. Prof. J. Matukas. 2010–2016.

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

Main publications:

Boppel, S., Ragauskas, M., Hajo, A., Bauer, M., Lisauskas, A., Chevtchenko, S., Rämer, A., Kašalynas, I., Valušis, G., Würfl, H-J., Heinrich, W., Tränkle, G., Krozer, V., Roskos, H. G. 2016. 0.25-um GaN TeraFETs Optimized as THz Power Detectors and Intensity-Gradient Sensors. IEEE Trans. Terahertz Science Technol., vol. 6, no. 2, p. 348–350, doi: 10.1109/TTHZ.2016.2520202.

Bauer, M., Boppel, S., Zhang, J., Rämer, A., Lisauskas, A., Heinrich, W., Krozer, V., Roskos, H. G. 2016. Optimization of the design of terahertz detectors based on Si CMOS and AlGaN/GaN field-effect transistors. Int. J. High Speed Electronics and Systems, vol. 25, No. 3 & 4 1640013, doi: 10.1142/S0129156416400139.

Lisauskas, A., Rämer, A., Burakevič, M., Krozer, V., Heinrich, W., Roskos, H. G. 2016. Terahertz emission from large AlGaN/GaN field-effect transistors. IEEE Proc. 41st Int. Conf. on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz, doi: 10.1109/IRMMW-THz.2016.7758975.

Glemža, J., Matukas, J., Pralgauskaitė, S. 2016. Low frequency noise spectroscopy and threshold characteristics of laser diodes. IEEE Proc. Microwave, Radar and Wireless Communications (MIKON), 21^st int. conf. May 9–11, 2016, Krakow, Poland, p. 1–4, doi: 10.1109/MIKON.2016.7491951.

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:

Kežionis, A., Petrulionis, D., Kazakevičius, E., Kazlauskas, S., Žalga, A., Juškėnas, R. 2016. Charge carrier relaxation phenomena and phase transition in La₂Mo₂O₉ ceramics investigated by broadband impedance spectroscopy. Electrochimica Acta, vol. 213, p. 306–313.

Zarkov, A., Stanulis, A., Salkus, T., Kezionis, A., Jasulaitiene, V., Ramanauskas, R., Tautkus, S., Kareiva, A. 2016. Synthesis of nanocrystalline gadolinium doped ceria via sol–gel combustion and sol–gel synthesis routes. Ceramics International, vol. 42, p. 3972–3988.

Emery, J., Šalkus, T., Abramova, A., Barré, M., Orliukas, A.F. 2016. NMR investigations in Li_1.3Al_0.3Ti_1.7(PO₄)₃ ceramics. Part I: Structural aspect. J. Phys. Chem. C, vol. 120(46), p. 26173–26186.

Emery, J. Salkus, T. Barré, M. 2016. NMR investigations in Li_1.3Al_0.3Ti_1.7(PO₄)₃ ceramics Part II: Lithium Dynamics, Experiments, and Model. J. Phys. Chem. C, vol. 120(46), p. 26235–26243.

Acoustic Investigations of Complex Structures. Dr. R. Rimeika. 2013–2017.

The propagation of leaky surface acoustic waves in complex lithium niobate/tantalate based structures has been investigated. The role of acoustoelectric interaction on the nanofilm-coated piezoelectric crystal surface and at the crystal-liquid interface has been investigated. The strong dependences of reflected wave amplitude and phase on liquid conductivity were observed and explained by acoustoelectric interaction in the wave reflection region.

Main publication:

Rimeika, R., Čiplys, D., Jonkus,V., Shur, M. 2016. Acoustoelectric effects in reflection of leaky-wave-radiated bulk acousticwaves from piezoelectric crystal-conductive liquid interface. Ultrasonic, vol. 64, p. 196–199.

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

Experimental investigation of electromagnetic compatibility of Digital Video Broadcasting - Terrestrial receivers operating below 790 MHz band with LTE base stations operating in 800 MHz band was carried out. The results obtained provide protection ratio and overloading threshold for the digital TV receivers in different operating scenarios which serve as a reference guide for regulatory authority, mobile operators and terrestrial TV providers.

Main publications:

Aleksandravicius, J., Krivochiza, J., Aleksiejunas, R., Svirskas, K., Zilinskas, M. 2016. Electromagnetic Compatibility Analysis of DVB-T and LTE Systems. Elektronika ir Elektrotechnika, vol. 22, no 4.

Aleksiejunas, R. 2016. Commentary on A. Habib and M. Rupp (2012), Antenna Selection in Polarized Multiple Input Multiple Output Transmissions with Mutual Coupling. Integrated Computer-Aided Engineering, vol. 23, no. 2, p. 201–202, doi: 10.3233/ica-150504.

International Research Projects

Swiss-Lithuanian Ferroelectrics: From Controlled Internal Fields to Energy Harvesting / Medical Diagnostics / Microelectronic Applications SLIFE (No. CH-3-ŠMM-01/02). Prof. J. Banys. 2012–2016.

The main scientific interest in this project is oriented along two main directions: (i) creation high-density charged/uncharged domains in single crystals, (ii) domain engineering in epitaxial thin films.

The most successful results on bulk crystals were achieved with barium titanate (BTO). This material allowed development and application of two different methods which have high potential of creating charged domain walls. Conductive transparent electrodes were deposited onto the BTO crystals. This allowed visual observation of the change of domain structure in the crystals during the poling procedures. It was found, that electromechanical coupling of the crystals was influenced by the domain structure. It is demonstrated, that the charged domain walls form in <110>-cut crystals in a more regular pattern when compared to <111>-cut ones. This leads to better piezoelectric properties and higher electromechanical coupling in <110>-cut BTO crystals.

It was experimentally shown, that strained BST and PMN-PT films have a significantly higher ferroelectric transition temperature compared to their bulk counterparts. This allows tailoring the desired electrical properties in a wider compositional range. Furthermore, BST, PMN-PT, PZT and PST films exhibited high electrical tunability, which is often unachievable for other synthesis techniques. Moreover, additional functionality, such as tunability of charge carrier mobility and/or concentration is possible by external stimulus, making these materials viable for oxide-based electronics.

Main publications:

Mackevičiūtė, R., Ivanov, M., Bagdzevičius, Š., Grigalaitis, R., Banys, J. 2016. Electrical model of a thin dielectric film with a bottom electrode of non-negligible distributed resistance. Ferroelectrics, vol. 497, p. 114–125.

Bagdzevicius, S., Mackeviciute, R., Ivanov, M., Fraygola, B., Sandu, C. S., Setter, N., Banys, J. 2016. Internal electrical and strain fields influence on the electrical tunability of epitaxial Ba_0.7Sr_0.3TiO₃ thin films. Appl. Phys. Lett., vol. 108, 132901.

Mackevičiūtė, R., Bagdzevičius, Š., Ivanov, M., Fraygola, B., Grigalaitis, R., Setter, N., Banys, J. 2016. Strain engineering of electrical conductivity in epitaxial thin Ba_0.7Sr_0.3TiO₃ film heterostructures. Lithuanian Journal of Physics, vol. 56, no. 3, p. 173–181.

Marie Curie Actions project: Fundamental and Applied Electromagnetics of Nano-Carbons FAEMCAR. Prof. J. Banys. 2012–2016.

During the developement of nanotechnlogy, the race for more and more compact and fast electronics raises many technological and fundamental problems. Due to their remarkable properties, carbon nanostructures may become part of future nanocircuits. Together with the increase of wireless telecommunication, our environment is more and more polluted with electromagnetic radiation. It often occurs that shielding, either the electromagnetic source or the sensitive device, provides the only valuable protection. Polymer composites loaded with various types of carbon nanostructures are well-suited candidates for this purpose.

Solving above mentioned problems different types of composite materials filledwith different kinds of carbon nanostructures have been made and characterized. The matrix of thecomposites can be a either a polymer, such as Epoxy, polymethyl methacrylate (PMMA),polystyrene, or a thermostable ceramic such as materials based on phosphate binding compositions.The carbon nanostructures used to load the matrix can be single-walled or multi-walled nanotubes (hyperfullerenes), exfoliated graphene, graphene nanoplatelets, carbon foam, carbon blacks. The nanocarbon fillers are used to increase the conductivity of the composite material and to modify its dielectric properties. By contrast, with nanodiamond for instance, the carbon nanostructures used are, or can be made, conducting. A dc current can flow through the composite if percolation paths exist along the embedded nanostructures. This is the reason why composites with composition close to the percolation threshold have been the subject of intensive characterization by different techniques.

In parallel to these experimental researches, theoretical models have been developed to understand the electromagnetic properties of nanocarbon-based composites. The models used so far are based either on effective medium theory or on the design of equivalent electric circuits involving randomly connected resistors, capacitors and diodes. The outcome is a model able to describe the frequency-dependent dielectric permittivity of the composite materials.

Main publications:

Plyushch, A., Macutkevic, J., Kuzhir, P., Banys, J., Fierro,V., Celzard, A. 2016. Dielectric properties and electrical conductivity of flat micronic graphite/polyurethane composites. Journal of Nanophotonics, vol. 10, p. 012511–1-12.

Plyushch, A., Macutkevic, J., Kuzhir, P., Banys, J., Bychanok, Dz., Lambin, Ph., Bistarelli, S., Cataldo, A. Micciulla, F. Bellucci, S. 2016. Electromagnetic properties of graphene nanoplates/epoxy composites. Composites Science and Technology, vol. 128, p. 75–83.

MSCA-RISE-2014: Marie Skłodowska-Curie Research and Innovation Staff Exchange Contractual Research project: TU Neable 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 for prospective application in forms of films and/or arranged layers in which the cross-coupling (magnetic-dipolar-elastic) can be tuned by both internal and external factors. This objective is to be achieved through preparation, investigation, and optimization of two kinds of Bi-containing oxygen-octahedral (BCOO) systems with paramagnetic ions involved: metastable perovskites and layered double hydroxides (LDHs). Polarization in such metastable perovskites is easily switched by application of external pressure (or stress in the case of films). Besides, a tuneability and high sensitivity of their properties to external stimuli make them promising for applications in sensors.

The results of measurements of dielectric and ferroelectric properties of the perovskite Bi_1-xLa_xFe_1-ySc_yO₃ ceramics synthesized/sintered under high pressure either from the mixed oxide precursors or from the precursors prepared using a sol-gel method were obtained. It was demonstrated that the properties of the ceramics of the same composition are comparable and reproducible regardless of the precursor used. The observed anomalies of the temperature-dependent dielectric permittivity are in good agreement with the phase transitions revealed from the in situ temperature diffraction studies. However, the ceramics synthesized/sintered from the mixed oxides were found to contain numerous cracks and other defects which contribute to the total electrical conductivity and to the ferroelectric domain pinning. The ceramics sintered from the sol-gel prepared powders were more homogenous, less leaky and demonstrated higher dielectric permittivity.

Bilateral Lithuanian-Japanese partnership project: Dielectric and Piezoelectric Enhancements of New Nano-structured Ceramics with High-density Artificially-made Extrinsic MPB Structures. Assoc. Prof. M. Ivanov. 2016–2018.

The main aim of the project – development of a new artificially made extrinsic morphotropic phase boundary (MPB) in nanostructured ceramic, not through usual route of mixing constituents in the same ceramic grain, but through epitaxial strain of two different (different material) composite grains via controlled fabrication of nanostructured ceramic.

MPB of PZT ceramics and relaxor-PT based single crystals shows the largest figures of merits for piezoelectric applications; nevertheless lead-free materials have some advantages – higher coercive fields and higher ferroelectric transition temperatures. Main problem is related to lower than lead-based materials’ piezoelectric coefficients; a lot of scientists are working towards improved lead-free piezoelectrics.

Objectives of the project are creation of extrinsic MPB in BaTiO₃/KNbO₃ nanostructured ceramics, improvement of the density of nanostructured ceramics, experimental confirmation of enhanced piezoelectric properties, investigation of dielectric properties of newly created materials in broad frequency and temperature ranges, design and construction of new polarization measurement cell (vacuum cell for ferroelectric hysteresis measurement) and further collaboration between two laboratories (strengthening of collaboration between Lithuanian and Japanese scientific institutions).

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

The aim of the project is to investigate the dielectric spectra covering 18 orders of magnitude in frequency of relaxor ferroelectric single crystals. Single crystals with different degree of doping are investigated. Such heterogeneity in crystals is responsible for the dielectric dispersion of relaxors. It is well established that random fields arising from the charge disorder in the cell determines the properties of such materials. This research is important to understand the impact of random fields for the microwave dielectric properties of relaxor ferroelectrics. The different strength of random fields is achieved by different kind of doping in the material. The materials possessing strong random fields will be compared with crystals which have isovalent substitutions.

The collaboration between Lithuanian group and Japanese is essential for the success of the project. Both groups have unique experimental techniques which allow obtaining significant results in the science of relaxor ferroelectrics. Combination of terahertz and microwave experimental data will allow covering whole broad frequency range without any gaps in the middle. Furthermore, lattice dynamics is thoroughly studied by Raman and infrared spectroscopic techniques.

Lithuanian-Swiss Institutional Partnership project: Broadband Impedance Study of Memristor Oxide Films (No. CH-3-ŠMM-02/06). Dr. T. Šalkus. 2016.

The project was devoted to the production of oxide thin films by PLD method and their detailed analysis by impedance spectroscopy. Strontium titanate and gadolinium doped ceria thin films were grown and the electrodes for electrical characterization were prepared. The impedance spectroscopy measurements were performed with the modified broadband impedance spectrometer at high frequencies up to 10 GHz. The films can find a potential application in the new generation memory elements, memristors. The understanding of physical reasons for memristor element switching was the main aim of the project.

OTHER SCIENTIFIC ACTIVITIES

Prof. Habil. Dr. J. Banys –

Chairman of the international conference 4^th Lithuanian-Ukrainian-Polish Meeting on Physics of Ferroelectrics (LUP-2016) (http://www.lup.ff.vu.lt).

DEPARTMENT OF SEMICONDUCTOR PHYSICS

3 Saulėtekio, LT-10257 Vilnius
Tel. 223 4502, fax 223 4482
E-mail:

Head – Prof. Habil. Dr. Gintautas Tamulaitis

STAFF

Professors: Habil. Dr. E. Gaubas (part-time), Habil. Dr. K. Jarašiūnas (professor emeritus), Habil. Dr. S. Juršėnas (part-time), Habil. Dr. Ž. Kancleris (part-time), Habil. Dr. V. Kažukauskas (part-time), Habil. Dr. E. Kuokštis, Habil. Dr. L. Subačius (part-time), Dr. V. Tamošiūnas, Habil. Dr. G. Tamulaitis (part-time), Dr. R. Tomašiūnas (part-time), Habil. 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).
Lecturers: 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).

Assistants: D. Meškauskas, Dr. L. Minkevičius (part-time).
Research fellows: Dr. D. Dobrovolskas, Dr. J. Jurkevičius, Dr. J. Mickevičius.
Doctoral students: M. Černauskas, M. Dmukauskas, K. Gelžinytė, O. Kravcov, D. Meškauskaitė, D. Meškauskas, K. Nomeika, J. Pavlov, A. Petrulis, Ž. Podlipskas, S. Raišys, I. Reklaitis, V. Rumbauskas, M. Skapas, A. Tekorius, A. Vaitkevičius, A. Zabiliūtė-Karaliūnė.

RESEARCH INTERESTS

Spectroscopic characterization of novel inorganic and organic semiconductor materials for optoelectronics
Optical nonlinearities in semiconductors caused by free carriers, electrooptic and spin-related mechanisms
Dynamics of nonequilibrium carriers and excitons in highly excited semiconductors and their low-dimensional structures
Radiation detectors, high-density scintillation crystals
Applications of light emitting diodes
Computer simulation of crystal surface and defects
Bio-, immuno-, DNA- sensors based on nanostructured conducting polymers

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

Centre for Physical Sciences and Technology (Lithuania)
Rensselaer Polytechnic Institute, Troy, NY (USA)
Sensor Electronic Technology, Inc., Columbia, SC (USA)
National Taiwan University, Taipei (Taiwan)
Interuniversity Microelectronic Centre IMEC (Belgium)

OTHER SCIENTIFIC ACTIVITIES

Prof. E. Kuokštis –

member of the Research Council of Lithuania, http://www.lmt.lt/indexe.php.

DEPARTMENT OF SOLID STATE ELECTRONICS

3 Saulėtekio, LT-10257 Vilnius
Tel. 223 4544
E-mail

Head – Prof. Dr. Kęstutis Arlauskas

STAFF

Professors: Dr. K. Arlauskas, Dr. V. Karpus (part-time), Habil. Dr. Emeritus G. Juška.

Associate professors: Dr. A. Poškus, Dr. M. Viliūnas, Dr. V. Jankauskas (part- time), Dr. R. Maldžius (part-time).

Senior research fellows: Dr. R. Rinkūnas, Dr. K. Genevičius, Dr. N. Nekrašas, Dr. V. Jankauskas (part-time), Dr. R. Maldžius (part-time), Dr. G. Sliaužys. Dr. L. Tumonis.

Junior research fellows: B. Lenkevičiūtė, E. Kamarauskas, T. Grigaitis, R. Dobužinskas, J. Važgėla.

Doctoral students: T. Grigaitis, B. Lenkevičiūtė, E. Kamarauskas, R. Dobužinskas, V. Sabonis, A. Aukštuolis, J. Nekrasovas, J. Važgėla, M. Stephen.

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 2016

Project Supported by University Budget

Solid State Physics and Technologies. Prof. K. Arlauskas, 2014–2017.

CELIV technique has been adapted for analysis of dispersive transport and it has been applied for investigation of the lead oxide X-rays detectors. Perovskite solar cells and hybrid systems with titanium (zinc) oxide and new hole transporting polymers has been under investigation using modified i-CELIV technique.

Main publication:

Semeniuk, O., Juska, G., Oelerich, J.O., Wiemer, M., Baranovskii, S.D., Reznik, A. 2016. Charge transport mechanism in lead oxide revealed by CELIV technique. Scientific Reports, vol. 6, 33359.

Features and modelling of charge carrier transport and recombination in disordered structures.

Influence of the morphology of the materials on the charge carrier transport.

Main publications:

Juška, G., Arlauskas, K., Genevičius, K. 2016. Charge carrier transport and recombination in disordered naterials. Lithuanian Journal of Physics, vol. 56, no. 3, p. 182–189.

Pivrikas, B., Philippa, R., White, D., Juska. G. 2016. Photocarrier lifetime and recombination losses in photovoltaic systems. Nature Photonics, vol.10, p. 282–283.

Stephen, M., Hasina, R., Santos-Silva, H., Dowland, S., Bégué, D., Genevicius, K., Arlauskas, K., Juska, G., Morse, G., Distler, A., Hiorns, R. 2016. Sterically controlled azomethine cycloaddition polymerization of phenyl-C61-butyric acid methyl ester. Chem.Commun., vol. 52 (36), p. 6107–6110, doi: 10.1039/C6CC01380E.

The all chinoline and 1,8-naphtyridine derivatives with different substituents as well as OLEDs based on emissive layers made from these compounds and hybrid OLEDs based on material Ir(Fppy)₃and on CdS_xSe_1-x/ZnS QDs, have been deposited and their electrical, photoelectrical, photoluminescence and electroluminescence features have been investigated.

Using three electrode PE CVD deposition system the optimal technology of deposition of SiN_x/a‑Si:H superlattices have been evaluated. The electrical, optical and electroluminescence (EL) features of these structures have been investigated. After doping of the SiN_x layer by Ce atoms, an additional EL maximum in the 480 – 540 nm range of wavelength has been obtained.

In 2016, the code MCNelectron (for Monte Carlo simulation of coupled electron-photon transport) was developed further, and it was used for simulations of generation of characteristic X-rays by kiloelectronvolt electrons. The results of those simulations were published in Nucl. Instr. and Meth. in Phys. Res. B 383 (2016) 65.

Main publications:

Poskus, A. 2016. Evaluation of computational models and cross sections used by MCNP6 for simulation of characteristic X-ray emission from thick targets bombarded by kiloelectronvolt electrons. Nuclear Instruments & Methods in Physics Research, B, vol.383, p. 65–80.

Poskus, A. 2016. Evaluation of computational models and cross sections used by MCNP6 for simulation of electron backscattering. Nuclear Instruments & Methods In Physics Research Section, B, vol. 368, p. 15–27.

The growth of KCl salt crystals from saturated solutions under the influence of X-ray radiation of different insulation conditions has been investigated. Insulation by X-rays up to 100 times increased the rate of KCl crystal growth.

The changes of paper pulp characteristics under DC electric current flow or due to applied rectangular current pulses of various frequencies was examined. The structure of paper before and after treating by ionizing voltage has been investigated.

Main publication:

Kalade, J., Rinkunas, R., Purlys, R., et al. 2016. The dynamics of the electric field distribution in the surface of insulating film irradiated by air ions. Materials Science-Medziagotyra, vol. 22 (1), p. 126–131.

The uncoated side of dispersion-barrier-coated paperboards was exposed to positive and negative direct current corona treatments in order to confirm the occurrence of backside treatment and clarify its effects on the usability of the paperboard. Coatings with a high talc proportion showed excellent initial grease resistance, but corona-induced strikethroughs caused a drastic decrease in grease penetration time. The alterations in surface free energies and rapeseed oil contact angles confirmed the occurrence of backside treatment. X-ray photoelectron spectroscopy results verified that backside treatment occurs also when the barrier-coated side of the substrate is treated with corona, indicating that a dispersion coating layer does not prevent this undesired phenomenon.

The adjustable voltage source of 0 – 600 V 0,1 Hz - 100 KHz for investigation of paper properties has been designed.
The high voltage contoller for impact ionised electron registration device (working region 2 - 4.5 kV) has been designed.

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

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

Ordered Research Project

Research Cooperation Contract: Omega. Coordinators: Stora Enso Oyj, Finland, Vilnius University, Lithuania. 2016.

Consulting Agreement. Lappeenranta University of Technology, Finland. 2016.

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

Prof. Habil. Dr. G. Juška

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

DEPARTMENT OF THEORETICAL PHYSICS

9 Saulėtekio, LT-10222 Vilnius
Tel. 236 6030, fax 236 6003
E-mail:

Head – Prof. Habil. Dr. Leonas Valkūnas

STAFF

Professors: Prof. Habil. Dr. L. Valkūnas (part-time), Prof. Habil. Dr. K. Pyragas (part-time), Prof. Dr. D. Abramavičius, Prof. Dr. E. Anisimovas, Prof. J. Šulskus.

Associate professors: Dr. J. Bučinskas, Dr. K. Glemža, Dr. T. Gajdosik, Dr. M. Mačernis, Dr. O. Rancova.
Lecturers: Dr. V. Balevičius, Dr. S. Toliautas, Dr. V. Butkus, Dr. J. Chmeliov.
Doctoral students: V. Abramavičius, V. Chorošajev, V. Dūdėnas, A. Gelžinis, A. Stepšys.

Processes Modeling Laboratory at the Department of Theoretical Physics

Head – Dr. Mindaugas Mačernis

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 the theoretical background of multi-dimensional spectroscopy of molecular complexes characterized by exciton spectra and charge-transfer states

Modelling of single molecular spectroscopy data of complex systems

RESEARCH PROJECTS CARRIED OUT IN 2016

Project Supported by University Budget

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

Theoretical background for studies of the energy transfer processes and coherent phenomena was devolped and used by investigating one-colour and two-colour two-dimensional electronic spectroscopy of various photosynthetic pigment-protein complexes. Theoretical analysis of the excitation transfer and relaxation pathways in various nanosystmes, such as carbon nanotubes, hybride perovskites, light-harvesting compelxes of photosystem II (LHCII) from plants was carried out.

Main publications:

Chmeliov, J., Gelzinis, A., Songaila, E., Augulis, R., Duffy, C. D. P., Ruban, A. V., Valkunas, L. 2016. The nature of self-regulation in photosynthetic light-harvesting antenna. Nature Plants, vol. 2, p. 16045.

Chmeliov, J., Narkeliunas, J., Graham, M. W., Fleming, G. R., Valkunas, L. 2016. Exciton-exciton annihilation and relaxation pathways in semiconducting carbon nanotubes. Nanoscale, vol. 8, p. 1618–1626.

Abramavicius, D., Valkunas, L. 2016. Role of coherent vibrations in energy transfer and conversion in photosynthetic pigment-protein complexes. Photosynth. Res., vol. 127, p. 33–47.

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 LHCII trimers and their aggregates across a wide temperature range were carried out in the experimental group of the partners. Within the frame of our studies we associate the red-emitting state, having fluorescence maximum at ∼700 nm, with the partial mixing of excitonic and chlorophyll–chlorophyll charge transfer states. The quenched state has a totally different nature and is related to the incoherent excitation transfer to the short-lived carotenoid excited states. 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. We demonstrated that depending on the amount of inhomogeneous broadening, the excitonically coupled molecular system can establish long-lived electronic coherences, caused by a disordered subensemble, for which the dephasing due to static energy disorder becomes significantly reduced.

Main publications:

Butkus, V., Dong, H., Fleming, G. R., Abamavicius, D., Valkunas, L. 2016. Disorder-induced quantum beats in two-dimensional spectra of excitonically coupled molecules. J. Phys. Chem. Lett., vol. 7, p. 277–282.

Wang, H., Valkunas, L., Cao, T., Whittacker-Brooks, L., Fleming, G. R. 2016. Coulomb screening and coherent phonon in methylammonium lead iodide perovskites. J. Phys. Chem. Lett., vol. 7, p. 3284–3289.

Farooq, S., Chmeliov, J., Trinkunas, G., Valkunas, L., van Amerongen, H. 2016. Is there excitation energy transfer between different layers of stacked photosystem II containing thylacoid membranes? J. Phys. Chem. Lett., vol.7, p. 1406–1410.

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 main topic is the application of theoretical quantum relaxation concepts to describe molecular non-equilibrium processes and to describe linear and non-linear optical spectroscopy in a broad range of temperatures. In one direction the theoretical and computational approaches were applied to study separate molecules strongly coupled to vibrational degrees of freedom. The latter causes vibrational progression in spectra and causes vibrational relaxation in time-resolved measurements. We created computational tools to describe pump-probe experiments of carotenoid molecules. The results were tightly correlated with experiments and resulted in two scientific publications. In the second direction the theoretical approaches were extended and applied to study small molecular aggregates using density matrix and stochastic wave function approaches. We described experimental hole-burning spectra of photosynthetic bacterial reaction center and came up with a new model for the system. The study resulted in two scientific publications. In the third direction we used stochastic wave function approaches to describe electron separation from hole in molecular solar cell. We showed that quantum wave-like properties of electron are necessary to include and this is the main reason for fast and efficient electron separation. The study resulted in one publication in a prestigious journal.

Main publications:

Abramavicius, D., Valkunas, L. 2016. Artificial photosynthesis: theoretical background. In R. Bruno (ed.), Artificial Photosynthesis, Elsevier Ltd., p. 129–167.

V. Balevičius, Jr., D. Abramavicius, T. Polívka, A. G. Pour, J. Hauer, J. 2016. A Unified Picture of S* in Carotenoids. Phys. Chem. Lett., vol. 7, p. 3347−3352, doi: 10.1021/acs.jpclett.6b01455.

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 Physics Society;
head of the Molecular Compounds Physics department at the Centre for Physical Sciences and Technology in Vilnius;
Doctor Philosophiae Honoris Causa of the Bogolyubov Institute for Theoretical Physics of the National Academy of Sciences of Ukraine.

Prof. K. Pyragas –

editorial board member of the Journal International Journal of Bifurcation and Chaos (IJBC) in Applied Sciences and Engineering;
editorial board member of the journal International Review of Physics (IREPHY);
editorial board member of the journal Chaos & Complexity Letters, International Journal of Dynamical Systems Research;
editorial board member of the journal Nonlinear Phenomena in Complex Systems, An Interdisciplinary Journal;
editorial board member of the journal Nonlinear Analysis Modelling and Control;
board member of the International Physics and Control Society;
board member of the Lithuanian Association of Nonlinear Analysis.

Prof. D. Abramavičius –

member of the American Physical Society.

Assoc. Prof. T. Gajdosik –

member of the Austrian Physical Society.