Faculty of Physics

Sukurta: 10 September 2013

ff9 Saulėtekio, LT-10222 Vilnius
Tel. 236 6001, fax 236 6003
E-mail:
http://www.ff.vu.lt

Dean – Prof. Habil. Dr. Vytautas Balevičius

STAFF

67 teachers (64 holding research degree), 69 research fellows (50 holding research degree), 75 doctoral students.

 

RESEARCH AREAS

Solid State Physics and Technology
Spectrometric Characterization of Materials and Electronic/Molecular Processes
Laser Physics and Technology

DOCTORAL DISSERTATIONS MAINTAINED IN 2014

Š. Bagdzevičius.  Processing, structural and broadband dielectric characterization of strontium titanate and related perovskite ceramics and thin films.

L. Damalakienė. Fluorescence research on the uptake and intracellular localisation of colloidal Quantum dots and their effect on mechanisms of endocytosis.

M. Ivanov. Grain size effect on dielectric properties of ferroelectrics and relaxors.

J. Galinis. Research on spontaneous parametric down-conversion pumped by incoherent light sources.

D. Majus. Transient phenomena in femtosecond filamentation.

S. Toliautas. Electronic excitation processes of photoactive organic molecules.

A. Tuzikas. Niche applications of solid-state lighting with controllable colour-rendition, spatial, photochemical, and photobiological properties.

CONFERENCES ORGANIZED IN 2014

11th Nordic Femtochemistry Conference

MAIN SCIENTIFIC ACHIEVEMENTS IN 2014

Multi-functional laser facility Naglis was established on the basis of Vilnius University Laser Research Centre, one of the divisions of the Faculty of Physics, and is aimed at experimental scientific research in high intensity laser physics, extreme nonlinear optics, attosecond science, nanophotonics, terahertz technology and other laser technology related fields, enhanced scientific competitiveness and collaboration with researchers from EU and Lithuanian academic institutions by joint research or by providing international and national access, development and testing of new laser and optical technologies and scientific instruments in collaboration with high-tech companies and improvement of qualification of graduate and post-graduate students.

Belgio, E., Kapitonova, E., Chmeliov, J., Duffy, C. D. P., Ungerer, P., Valkunas, L., Ruban, A. V. 2014. Economic photoprotection in photosystem II that retains a complete light-harvesting system with slow energy traps. Nature Communication, vol. 5, 4433.

Fuller, F. D., Pan, J., Gelzinis, A., Butkus, V., Senlik, S. S., Wilcox, D. E., Yocum, C. F., Valkunas, L., Abramavicius, D., Ogilvie, J. P. 2014. Vibronic coherence in oxygenic photosynthesis. Nature Chem., vol. 6, 706–711.

ASTRONOMICAL OBSERVATORY

29 M. K. Čiurlionio, LT-03100, Vilnius
Tel. 239 8764, fax 239 8767
E-mail:

Head – Prof. Dr. Vladas Vansevičius

STAFF

Professors: Prof. Dr. V. Vansevičius, Dr. A. Kučinskas (part-time).
Associate professors: Dr. J. Sūdžius, Dr. A. Bridžius (part-time), Dr. D. Narbutis (part-time).
Senior research fellows: Dr. S. Bartašiūtė, Dr. J. Sperauskas.
Junior research fellows: V. Deveikis, S. Raudeliūnas.
Doctoral students: T. Mineikis, P. de Meulenaer.

RESEARCH INTERESTS

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

RESEARCH PROJECTS CARRIED OUT IN 2014

Projects Supported by University Budget

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

Main publications:

de Meulenaer P., Narbutis D., Mineikis T., Vansevičius V. 2014. Deriving physical parameters of unresolved star clusters. II. The degeneracies of age, mass, extinction, and metallicity. Astronomy & Astrophysics, vol. 569, A4.

Narbutis D., Semionov D., Stonkutė R., de Meulenaer P., Mineikis T., Bridžius A., Vansevičius V. 2014. Deriving structural parameters of semi-resolved star clusters. FitClust: a program for crowded fields.  Astronomy & Astrophysics, vol. 569, A30.

Narbutis D., Stunkutė R., de Meulenaer P., Mineikis T., Vansevičius V. 2014. Structural parameters of star clusters: stochastic effects. Baltic Astronomy, vol. 23, 103.

National Research Projects

Research Council of Lithuania: A Comprehensive Study of Pulsations, Binarity and Chemistry of Post-AGB Stars. Dr. J. Sperauskas. 2012–2014.

Main publications:

Sperauskas J., Zacs L., Raudeliunas S., Musaev F., Puzin V. 2014. HD 50975: a yellow supergiant in a spectroscopic binary system. A&A, 570, 3.

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

Centre for Physical Sciences and Technology (Lithuania)
National Astronomical Observatory of Japan

OTHER SCIENTIFIC ACTIVITIES

Dr. S. Bartašiūtė –

  • editorial board of the international journal Baltic Astronomy.

DEPARTMENT OF GENERAL PHYSICS AND SPECTROSCOPY

9 Saulėtekio, LT-10222 Vilnius
Tel. 236 6040, fax 236 6003
E-mail:

Head - Prof. Habil. Dr. Vytautas Balevičius

STAFF

Professors: Habil. Dr. V. Balevičius, Dr. G. Dikčius, Dr. V. Šablinskas, Dr. V. Gulbinas (part-time).
Associate professors: Dr. V. Aleksa, Dr. A. Gruodis, Dr. A. Maršalka, Dr. F. Kuliešius, Dr. J. Čeponkus, Dr. L. Juodis.
Lecturers: Dr. K. Aidas, Dr. V. Urbonienė.
Doctoral students: M. Pučetaitė, S. Tamošaitytė, V. Klimavičius, J. Kausteklis, N. Kelminskienė, N.  Karalius.

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

RESEARCH PROJECTS CARRIED OUT IN 2014

Projects Supported by University Budget

Spectroscopy of Molecular Processes in Biological and Mesoscopic Systems. Prof. V. Balevicius, Prof. V. Sablinskas. 2010–2014.

NMR relaxation processes of anions (Br–, Cl–) were studied in series of neat room temperature ionic liquids. In order to eliminate the acoustic ringing of the probe-head during relaxation times measurements the novel pulse sequence has been devised. The observed T1/T2 (1.27 - 1.44) ratios were found to be not sufficiently high to confirm the presence of long-living (on the time scale of ≥ 10–8 s) mesoscopic structures or heterogeneities in the studied neat ionic liquids. Oscillatory kinetics of 1H – 31P cross polarization in nano-structured materials over a wide range of contact time has been measured and described using variable cut-off distribution of the dipolar coupling and characteristic size profile of spin clusters determined.
Physical properties of some biologically relevant compounds have been studied by means of molecular modelling using advanced quantum chemical methods.
Fourier transform infrared (FT-IR) spectroscopy was applied to characterize the extracellular matrix (ECM) of kidney tumour tissue and normal kidney tissue.
Specular reflection infrared microspectroscopy was used for chemical imaging of cross-sectioned urinary stones to determine their chemical composition and morphology simultaneously.

Main publications:

Klimavicius V., Gdaniec Z., Balevicius V. 2014. Very short NMR relaxation times of anions in ionic liquids: New pulse sequence to eliminate the acoustic ringing. - Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, vol. 132, 879–883.

Klimavicius V., Kareiva A., Balevicius V. 2014. Solid-state NMR study of hydroxyapatite containing amorphous phosphate Ppase and nano-structured hydroxyapatite: cut-off averaging of CP MAS kinetics and size profiles of spin clusters.  J. Phys. Chem. C. doi:10.1021/jp510229f

Urboniene V., Pucetaite M., Jankevicius F., Zelvys A., Sablinskas V., Steiner G. 2014. Identification of kidney tumour tissue by infrared spectroscopy of extracellular matrix, JBO 19(8), 087005, [doi: 10.1117/1.JBO.19.8.087005].

National Research Projects

Research Council of Lithuania. Spectral Characterization of Silicon and Germanium Containing Functionalized Organic Cyclic Compounds. Assoc. Prof. V. Aleksa. (MIP-071/2013). 2013–2015.

Ab initio and DFT calculations were carried out for three newly synthesized Si containing organic compounds. The theoretical results were compared with experimental vibrational spectra. Geometrical parameters for three newly synthesized cyclic compounds were found.

European Social Fund Agency. Synthesis and Spectroscopical Characterization of Materials Important for Semiconductor- and Nano-Technologies. Prof. V. Sablinskas (No. VP1-3.1- ŠMM-08-K-01-004/KS-120000-1756). 2013–2015.

Some hydroapatites were synthesized and spectroscopically analysed. Silver nanoprisms for enhancement of Raman signal were synthesized. It was found that the prisms give better enhancement than nanospheres and nanorods.

Agency for Science, Innovation and Technology. Development of Spectroscopic UV-VIS-NIR Analyzers for Multiparameter Characterization of Dispersive Flows. (Nr. VP2-1.3-ŪM-02-K-04-063). Prof.V. Sablinskas - contact person from VU. 2013–2015.

The analyser for quantitative analysis of powdered mixtures was designed and prototype of such an analyser was constructed. The analyser is based on ATR technique. It was found that sufficient reproducibility of results captured by the analyser can be achieved when spectra of 16 or more independent samples are averaged.

International Research Projects

EU research project in the frame of Integrating Activity on Synchrotron and Free Electron Laser Science (IA-SFS) program: Application of Synchrotron Based Infrared Spectral Microscopy of Intercellular Fluid for Detection of Cancerous Kidney Tissue Areas. Prof. R. Nyholm (Swedish National Laboratory of Synchrotron Radiation, Lund). Prof. V. Šablinskas (Vilnius University). 2014.

It was found that by using synchrotron radiation as a source high quality absorption spectra in far infrared spectral region can be obtained. The spectra can be used for determination of cancerous areas in biological tissue.

Contractual Research

MITA innovation cheque UV-VIS-IR and Raman Measurements of Polymeric Samples.  (Contract Nr. ŪST-(SPR-1306)-1/1). Prof. V. Balevičius.

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

Institute of Physics (National Centre of Physical and Technological Sciences, Lithuania)
Technical Universities of Darmstadt and Dresden (Germany)
Paris Sud 11 University (France)
Institute of Bioorganic Chemistry of Polish Academy of Sciences, Poznan (Poland)
National Institute of Chemistry (Slovenia)

OTHER SCIENTIFIC ACTIVITIES

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.

Prof. G. Dikčius –

  • national coordinator for the EMSPS scheme (mobility of students of physics);
  • ERASMUS coordinator for physics;
  • member of EUPEN network

DEPARTMENT OF QUANTUM ELECTRONICS

9 Saulėtekio, LT-10222 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, Habil. Dr. B. Kaulakys (part-time), Habil. Dr. A. Piskarskas (emeritus), Habil. Dr. A. Stabinis (emeritus).
Chief research fellow: Dr. A. Varanavičius.
Associate professors: Dr. S. Bagdonas, Dr. A. Matijošius, Dr. O. Balachninaitė, Dr. V. Karenauskaitė, Dr. M. Vengris, Dr. V. Jarutis, Dr. A. Melninkaitis, Dr.V. Pyragaitė, Dr. V. Kudriašov, Dr. A. Čiuplys (part-time).
Senior research fellows: Dr. V. Vaičaitis, Dr. E. Gaižauskas, Dr. M. Malinauskas, Dr. R. Grigonis, Dr. R. Butkus, Dr. G. Tamošauskas.
Research fellows: Dr. D. Kaškelytė, Dr. M. Peckus.
Lecturers: J. Jurkienė, Dr. R. Butkus (part-time), Dr. G. Tamošauskas (part-time), Dr. D. Paipulas (part-time), Dr. R. Piskarskas.
Head of the teaching laboratory: A. Čiburys.
Doctoral students: L. Damalakienė (until October 2014), A. Savickas, J. Galinis, A. Baškevičius, T. Kudrius, D. Kezys (until April 2014), V. Purlys (until October 2014), D. Majus, E. Gabrytė, V. Voiciuk, T. Stanislauskas, A. Žukauskas, G. Batavičiūtė, A. Alesenkov, M. Matulionytė, L. Mažulė, S. Rėkštytė, K. Redeckas, K. Stankevičiūtė, K. Steponkevičius, K. Michailovas, I. Pipinytė, P. Stanislovaitis, J. Vengelis (from October 2014).

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 and 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 photo physical 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
Nonlinear optics of Bessel beams
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

RESEARCH PROJECTS CARRIED OUT IN 2014

Projects Supported by University Budget

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

An optical parametric amplifier pumped by a Bessel beam was investigated. The effect was elucidated by the numerical simulations as well as experiment. The explanation by the derived eigenvalue problem was given.
Theoretically and experimentally the generation of optical vortices using an S-wave-plate fabricated by femtosecond laser writing in silica glass was demonstrated. It is shown that this method allows forming opthogonally polarised vortices with fractional topological charge. At the double wavelength of the S-waveplate, the superposition of orthogonally polarised optical vortices with topological charge ½ was generated.
Spectroscopic studies on indolo-benzoxazine type photochromic switches and cyanine dyes were performed. The primary characterization of molecular properties and detailed investigation of forward and backward switching dynamics was characterized using steady state absorption, nanosecond-microsecond transient absorption and multi-pulse transient absorption techniques. Using the mentioned experimental techniques, carrier dynamics was investigated in InGaN/GaN quantum structures.

Main publications:

Kezys D., Pyragaite V., Stabinis A, Butkus R., Smilgevicius V. 2014. Influence of parametric diffraction on conversion efficiency in two-beam-pumped optical parametric amplifier, Optics Communication, vol. 324, 58–62.

Matijosius A., Stanislovaitis P., Gertus T., Smilgevicius V. 2014. Formation of optical vortices with topological charge l=1/2 by use of the S-waveplate, Optics Communications, vol. 324, 1–9.

Steponkevičius K., Pyragaite V., Makauskas B., Žeimys E., Vaičaitis V. 2014. Spectral  shifts of the fundamental and third harmonic radiation in air induced by self-focused femtosecond laser pulses Opt. Commun., vol. 333, 71–74.

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

Study of light-matter interaction mechanisms occurring in direct writing at micro/nano-scale of polymers employing ultrashort high repetition laser pulses was performed. Creation of composite material 3D microscaffolds as biomimetic environments for cell studies, combination of additive manufacturing technologies (thermal extrusion 3D printing with direct laser writing) for the creation of artificial polymer scaffolds for applications in stem cell growth, tissue engineering and regenerative medicine.
Fabrication and characterization of 3D photonic crystals inscribed in transparent solid media for control of light propagation at micro-scale. Research on technologies for artificial structural colours by nano-structuring of materials in 2.5 and 3D, study of influence of wavelength of femtosecond lasers on mechanisms and efficiency of direct laser writing in transparent media were carried out.
Studies of energy transfer processes in complexes of quantum dots and photosensitizer chlorin e(6), cellular uptake, photosensitizing properties and stability in living cells were performed.

Main publications:

Zukauskas A., Bataviciute G., Sciuka M., Jukna T., Melninkaitis A., Malinauskas M. 2014. Characterization of photopolymers used in laser 3D micro/nanolithography by means of laser-induced damage threshold (LIDT), Opt. Mat. Express, vol. 4(8), 1601–1616.

Rekstyte S., Kaziulionyte E., Balciunas E., Kaskelyte D., Malinauskas M. 2014. Direct laser fabrication of composite material 3D microstructured scaffoldings. J. Laser Micro. Nanoen., vol. 9(1), 25–30.

Valanciunaite J., Klymchenko A.S., Skripka A., Richert L., Steponkiene S., Streckyte G., Mely Y., Rotomskis R. 2014. A non-covalent complex of quantum dots and chlorin e(6): efficient energy transfer and remarkable stability in living cells revealed by FLIM. RSC Adv., 4, issue 94, 52270–52278.

National Research Projects

Fabrication of Micro/Nanooptical Elements by Means of Laser and Electron Beam Lithographies (MIKROŠVIESA). 2012–2014.

The main objective of the Project is to develop efficient prototyping of various microoptical and nanooptical components out of novel class hybrid photopolymers by direct writing using femtosecond lasers and electron beam lithography, additionally combining it with nanoimprint lithography (soft lithography replication) technique. Pursuing for this aim it is planned to solve several tasks: develop and optimize laser writing in polymers and their development after exposure, determine and select materials suitable for fabrication and application of microoptical and nanooptical components, assess their quality and characterize their performance, compare experimental results to theoretical estimations.
Knowledge and skills will be acquired for direct writing fabrication of complex shaped functional microoptical and nanooptical components such as: microlenses with phase gratings, Fresnel, aspheric and cylindrical bifocal microlenses as well as arrays of them. Furthermore, this approach will enable one to fabricate microstructures on various substrates (glass, metal, silicon) and integrate them into already existent sophisticated systems (tip of the fibre, microfluidics and optofluidic chips, solar cells).

Main publications:

Cheng, Y.C., Zeng, H., Trull, J., Cojocaru, C., Malinauskas, M., Jukna, T., Wiersma, D., Staliunas, K. 2014.  Beam Focalization in Reflections from Flat Dielectric Subwavelength Gratings, Opt. Lett., vol. 39(21), 6086–6089.

Malinauskas, M., Juodkazis, S. 2014. A decade of advances in femtosecond laser fabrication of polymers: mechanisms and applications. Micro- and Nanotechnologies, Springer Series in Materials Science, vol. 195, 271–291.

High Average Power <10 Fs Pulse Formation by Parametric Chirped Pulse Amplification Method. 2014–2016.

A research aiming at development of set up for generation of broadband CEP stable seed for parametric amplifiers has been performed. The broadband signal generation was achieved in continuum generator pumped by second harmonic of femtosecond Yb:KGW laser. It was parametrically amplified and the idler wave that is passively CEP stabilized is used as a pump for second continuum generator allowing for formation of seed pulse covering 500-1000 nm spectral range with energy of several nano joules. Then this signal is amplified in three stage femtosecond parametric amplifier increasing >250 nm spectral width pulse energy up to 30-40 µJ and maintaining high CEP stability. 

Formation of Coherent Radiation in Nonlinear Crystals by Incoherent Pump (Kost). 2013–2015.

Second-harmonic generation from incoherent conical beams was investigated. A theoretical description of an incoherent conical beam was provided. It was demonstrated that in the case of noncollinear phase matching the spectrum of the second-harmonic beam narrows with the propagation in a nonlinear crystal. A simplified experiment with two intersecting fundamental beams was described. Numerical simulations of the nonlinear coupling equations were performed and good agreement with the theory was obtained.

Main publications:

Stanislovaitis P., Narmontas A., Pyragaite V., Smilgevičius V. 2014. Generation of a coherent second-harmonic beam from incoherent conical beams, Phys. Rev. A, vol. 89, 043821.

Complete Characterization of Ultrafast Nonlinear Light-Matter Interactions in Transparent Dielectrics in the Infrared Spectral Range (COLMIR). 2013–2015.

By comprehensive experimental characterization (high dynamic range measurements of spatiotemporal intensity profiles, angularly resolved spectra, energy fluxes and free-space propagation) it is demonstrated that the light bullets emerging from filamentation of femtosecond laser pulses in dielectric medium with anomalous group velocity dispersion are polychromatic Bessel-like wave packets which bear the basic properties of the nonlinear O waves. As a consequence of this, the light bullets exhibit a rather remarkable behavior as they exit the sample and propagate in free space, i.e., in the absence of any nonlinear or dispersive effects: the bullets disperse temporally, yet continue to propagate with strongly suppressed diffraction. Moreover, due to conical energy flux, the light bullets are extremely robust to external perturbations and exhibit a property of complete spatiotemporal self-reconstruction after hitting an obstacle, which blocks its intense core carrying the self-compressed pulse, in nonlinear as well as in linear (free-space) propagation regimes.

Main publications:

Majus D., Tamošauskas G., Gražulevičiūtė I., Garejev N., Lotti A., Couairon A., Faccio,D., Dubietis,A. 2014. Nature of spatiotemporal light bullets in bulk Kerr media. Physical Review Letters, vol. 112, 193901.

Gražulevičiūtė I., Tamošauskas G., Jukna V., Couairon A., Faccio D., Dubietis A. 2014. Self-reconstructing spatiotemporal light bullets. Optics Express, vol. 22, 30613–30622.

International Research Projects

7FP Project Integrated European Laser Laboratories III (LASERLAB-Europe III). 2012–2014.

Three Joint Research Activities (JRA) are in action: within the JRA BIOPTICHAL, work station for multiphoton polymerization based on the use of femtosecond high repetition rate Yb:KGW laser was further developed;
within the JRA EURO-LITE, we explored possibilities for flat-top picosecond pulse formation by using the cascade second harmonic (SH) generation processes. Proposed shaping method is particularly suitable for the application in the multistage high contrast OPCPA pumped by SH of Nd:YAG lasers. This method of pump pulse formation was employed in 10 Hz rep. rate OPCPA system producing sub-10 fs pulses at TW power level;
within the JRA INREX, terahertz wave generation from air excited by tightly focused fundamental and second-harmonic pulses of a femtosecond Ti:sapphire laser is analysed both theoretically and experimentally for various pump pulse energies. Numerical calculations, based on the microscopic polarization model, revealed that the experimentally obtained dependencies of terahertz yield can be well explained taking into account phase shifts of bichromatic pump waves, acquired during free propagation in air, and nonlinear second-harmonic crystal, as well as by considering the Gouy phases of focused laser beams.

Main publications:

Stanislauskas T., Budriūnas R., Antipenkov R., Zaukevičius A., Adamonis J., Michailovas A., Giniūnas L., Danielius R., Piskarskas A., Varanavičius A. 2014. Table top TW-class OPCPA system driven by tandem femtosecond Yb:KGW and picosecond Nd:YAG lasers. Optics Express, vol. 22, 1865–1870.

Balčiūnas T., Flöry T., Baltuška A., Stanislauskas T., Antipenkov R., Varanavičius A., Steinmeyer G., 2014. Direct carrier-envelope phase control of an amplified laser system. Optics Letters, vol. 39, 1669–1672 , doi: 10.1364/OL.39.001669.

Pyragaitė V., Smilgevičius V., Steponkevičius K., Makauskas B., Vaičaitis V. 2014. Phase shifts in terahertz wave generation by tightly focused bichromatic laser pulses. JOSA B vol. 31, iss. 7, 1430–1435.

Project: Establishment of the Multi-Functional Laser Facility (NAGLIS).  2010–2014.

The construction of multi-functional laser facility Naglis is completed and the whole infrastructure functions according to specifications. Most of the equipment in the laboratories is installed and tested and experimental activities already started. The remaining small portion of supplemental equipment and computers will be delivered until the first quarter of 2015.

Research grant no. VP1-3.1-SMM-10-V-02-007 supported by European Social Fund Agency: Development and Utilization of a New Generation Industrial Laser Material Processing Using Ultrashort Pulse Lasers for Industrial Applications.
 
A new laser microfabrication system was installed in the facilities with integrated high power (up to 20 W) femtosecond laser in 2014. Using this system the research on rapid micro cutting of various glasses were carried out utilizing high power laser filaments and the optimal processing parameters were evaluated that yielded highest processing throughout. Additionally, research on volumetric material modification with femtosecond laser pulses were carried out: the successful integration of DOE inside sapphire crystal and formation of three-dimensional microfluidic channels in fused silica were demonstrated.

Main publications:

Butkus S., Gaižauskas E., Paipulas D., Viburys Ž., Kaškelytė D., Barkauskas M., Alesenkov A., Sirutkaitis V. 2014. Rapid microfabrication of transparent materials using filamented femtosecond laser pulses. Appl. Phys. A., vol. 114(1), 81–90.  

Butkus S., Gaižauskas E., Paipulas D., Sirutkaitis R., Sirutkaitis V. 2014. Rapid cutting and drilling of transparent materials via femtosecond laser filamentation, J. Laser Micro/Nanoeng., vol. 9(3), 213–220.

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

Swinburne University of Technology, Centre for Micro-Photonics (H34), Hawthorn, Victoria, (Australia)

Universitat PolitĆØcnica de Catalunya, Departament de Fisica i Enginyeria Nuclear, Terrassa  (Spain)

University of Patras, Physics Department, Laser, Nonlinear and Quantum Optics Labs (Greece)

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

CNISM and Dipartimento di Scienza e Alta Tecnologia, University of Insubria, Como (Italy).

OTHER SCIENTIFIC ACTIVITIES

Prof. V. Sirutkaitis –

  • member of Access Board of Laserlab-Europe 3;
  • member of Council on High Technology programme at Agency for Science, Innovation and Technology (MITA, Lithuania);
  • board member of Lithuanian Laser Association.

Prof. R. Rotomskis –

  • member of the Scientific Advisory Committee of the International Forum for Virtual Conferences Internet Photochemistry and Photobiology;
  • member of the Council of the European Society for Photobiology, Executive Representative of Photobiology Sciences for East European countries;
  • National representative of the Mirror Group of ETP Nanomedicine.

Prof. A. Dubietis -

  • member of the Optical Society of America;
  • member of the International Meteor Organization.

Dr. A. Melninkaitis -

  • member of the Optical Society of America;
  • board member of Lithuanian Laser Association.

 

DEPARTMENT OF RADIOPHYSICS

9 Saulėtekio, LT - 10222 Vilnius,
Tel. 236 6080, fax 236 6081
e-mail  

Head - Prof. Jonas Matukas

STAFF

Professors: Habil. Dr J. Banys, Habil. Dr. J. Matukas, Habil. Dr. V. Ivaška, Habil. Dr. A. F. Orliukas, Habil. Dr. D. Čiplys, Dr. A. Lisauskas.
Associate professors: Dr. V. Kalesinskas, Dr. V. Samulionis, Dr. A. Kežionis, Dr. V. Jonkus, Dr. R. Rimeika, Dr. V. Kunigėlis, Dr. M. Žilinskas, Dr. R. Sobiestijanskas, Dr. S. Pralgauskaitė, Dr. R. Grigalaitis, Dr. E. Kazakevičius, Dr. T. Šalkus.
Lecturers: Dr. K. Svirskas, Dr. R. Aleksiejūnas, Dr. Č. Pavasaris, Dr. R. Giriūnienė, Dr. K. Maknys, Dr. M. Ivanov, E. Palaimienė, S. Kazlauskas.
Research fellows: Dr. J. Vyšniauskas, Dr. J. Macutkevič, Dr. S. Lapinskas, Dr. V. Kalendra, Dr. A. Bernotas, Dr. A. Brilingas, Dr. Š. Bagdzevičius.
Engineering staff:  A. Sereika, V. Adomaitis, Dr. Č. Pavasaris.
Doctoral students:, E. Palaimienė, V. Venckutė, S. Kazlauskas, R. Mackevičiūtė, J. Aleksandravičius, J. Zdanevičius, J. Belovickis, J. Krivochiža, Š. Svirskas, Dž. Jablonskas, I. Kranauskaitė, M. Šimėnas, K. Ikamas, A. Plyushch, O. Varenyk, J. Shvalia.

RESEARCH INTERESTS

Propagation and interaction of acoustic waves in condensed matter
Propagation and interaction of acoustic waves in condensed matter; investigations of complex structures by acoustic methods
Broadband dielectric and ultrasonic spectroscopy of innovative materials
The investigation of technology conditions of the preparation and physical properties of superionic ceramics with fast oxygen vacancy and Li ions transport
Investigation of noise characteristics of quantum structure devices employed in telecommunication systems
Electromagnetic methods for increasing spectral efficiency of radio communication systems

RESEARCH PROJECTS CARRIED OUT IN 2014

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.

Main publications:

Macutkevic, J., Paddubskaya, A., Kuzhir, P., Banys, J., Maksimenko, S., Kuznetsov, V. L., Mazov, I. N., Krasnikov, D. V. 2014. Dielectric properties of polymer composites with carbon nanotubes of different diameter. Journal of Nanoscience and Nanotechnology, vol. 14, 5430.

Grigalaitis, R., Ivanov, M., Macutkevic, J., Banys, J., Carreaud, J., Kiat, J. M., Laguta, V. V, Zalar, B. 2014. Size effect in a relaxor: further insights into PMN. Journal of Physics Condensed Matter, vol. 26, 272201.

Pozingis, J., Macutkevic, J., Grigalaitis, R., Banys, J., Lupascu, D. C. 2014. Structure and dielectric properties of (1-x)Ag0.9Li0.1NbO3-(x)Bi0.5K0.5TiO3 ferroelectric ceramics. Ceramics International, vol. 40, 9961–9969.

The Investigation of Technology Conditions of the Preparation and Physical Properties of Some Superionic Ceramics with Fast Oxygen Vacancy and Li Ions Transport. Prof. Habil. Dr. A. F. Orliukas. 2011–2015.

The preparation conditions of Li+ and oxygen vacancy conducted solid electrolyte ceramics and investigation of the relationship between technological conditions of the preparation of the ceramics and their electrical properties in the frequency range from 1 Hz to 3 GHz in the temperature interval (300 – 1000)K.

Main publications:

Venckutė, V., Miškinis, J., Kazlauskienė, V., Šalkus, T., Dindune, A., Kanepe, Z., Ronis, J., Maneikis, A., Lelis, M., Kežionis, A., Orliukas, A. F. 2014. XRD, XPS, SEM/EDX and broadband impedance spectroscopy study of pyrophospahate LiFeP2O7 and Li0.9Fe0.9Tio.1P2O7) ceramics. Phase Transitions, vol. 87(5),  438-451.

Kazlauskas, S., Kežionis, A., Kazakevičius, E., Orliukas, A. F. 2014. Charge carrier relaxation and phase transition in scandium stabilized zirconia ceramics. Electrochimica Acta, vol. 134. 176–181.

Kezionis, A., Kazlauskas, S., Petrulionis, D., Orliukas, A. F. 2014. Broadband method for the determination of small samples electrical and dielectric properties at high temperatures. IEEE Transactions on Microwave Theory and Techniques, vol. 62, 2456–2461.

Noise Characteristics Investigation of Quantum Structure Devices Employed in Telecommunication Systems. Prof. J. Matukas. 2010–2015.

Investigation of low frequency noise and responsivity characteristics of CMOS transistor-based detectors for terahertz radiation has been carried out. The main noise origins are thermal channel noise and generation-recombination, also 1/f-type fluctuations.
Influence of aging processes to the high-power light emitting diodes noise and operation characteristics have been investigated. Degradation of different parts of device: active region, phosphors layer, secondary optics has been evaluated.

Main publications:

Bauer, M., Venckevičius, R., Kašalynas, I., Boppel, S., Mundt, M., Minkevičius, L., Lisauskas, A., Valušis, G., Krozer, V., Roskos, H. G. 2014. Antenna-coupled field-effect transistors for multi-spectral terahertz imaging up to 4.25 THz. OPTICS EXPRESS, vol. 22 (16), 19235–19241.

Palenskis, V. 2014. The effective density of randomly moving electrons and related characteristics of materials with degenerate electron gas. AIP advances, vol. 4 (4), 047119.

Lisauskas, A., Boppela, S., Bauer, M., Zdanevičius, J., Matukas, J., Krozer, V., Roskos, G. 2014. Terahertz detection with field-effect transistors: intrinsic versus device sensitivity limits in Advanced Photonics, OSA Technical Digest (online) (Optical Society of America, 2014), paper SeTu5A.2. http://www.opticsinfobase.org/abstract.cfm?URI=Sensors-2014-SeTu5A.2

Electromagnetic Methods for Increasing Spectral Efficiency of Radio Communication Systems. Assoc. Prof. 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 has been developed. 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, antenna analysis, radio propagation channel, radio interference estimation problems. Simulations are based on statistical Monte Carlo algorithm, implemented using GNU Octave and Python numerical libraries. An automated measurement test-bed was created, capable of accurate angle orientation of the user equipment antennas towards base station antennas, making possible to investigate angular downlink throughput diversity of the 2x2 MIMO system. Such a setup enabled gathering statistically reliable data by constantly repeating measurements over various configurations. The results of the measurements were used in the paper Analysis of Radar Interference Effects on MIMO LTE Downlink Performance.

Acoustic Investigations of Complex Structures. Prof. D. Čiplys. 2013–2017.

Investigation of light diffraction by shear horizontal acoustic waves in piezoelectric crystals was carried out revealing possibilities of novel acousto-optic applications. Stability of III-nitride based SAW delay-line oscillator was studied. The pulse acoustic spectroscopy technique for studies of porous films was developed.

Main publications:

Miškinis, R., Jokubauskas, D., Smirnov, D., Urba, E., Sereika, A., Rimeika, R., Čiplys, D. 2014. Dependence of oscillation frequency on temperature for a GaN-based surface acoustic wave oscillator. 12th School on Acousto-Optics and Applications: abstract and programme book, June 29–July 3, 2014, Druskininkai, 48-49.

Rimeika, R., Čiplys, D., Shur, M. S. 2014. Acousto-optic diffraction by shear horizontal surface acoustic waves in 36o rot. YX-LiTaO3. 12th School on Acousto-Optics and Applications: abstract and programme book, June 29–July 3, 2014, Druskininkai, 37–38.

National Research Projects

Complex Investigations of Multifferroic Properties in Composites and Nanoceramics (No VP1-3.1-ŠMM-07-K-03-011). Dr. R. Grigalaitis. 2013–2015.

Various types of multiferroic composites were investigated by the broadband dielectric spectroscopy. First, the lead-free composites based on barium titanate and nickel/zinc ferrites prepared by different methods were examined. It was found that the synthesis method of the composite itself and even of its constituents makes a high impact on its low-frequency dielectric permittivity behaviour which is typically caused by Maxwell-Wagner-type relaxation processes in grain and inter-grain medium. The reduction of the interaction volume between the neighbouring grains suppresses also the ferroelectric properties of the composites due to the decrease of the long-range interaction. This is especially clearly evident in ceramics prepared by core-shell technology where ferromagnetic cores are surrounded by ferroelectric shell.
To compare the dielectric response of above mentioned composites with another types of multiferroics, the broadband dielectric spectroscopy of tetragonal tungsten bronze solid solutions and lead-based composites where ferroelectric constituent is replaced by lead zirconate titanate have been started and analysed.

Main publications:

Grigalaitis, R., Vijatović, M., Petrović, M., Bobić, J. D., Dzunuzovic, A, Sobiestianskas, R., Brilingas, A., Stojanović, B. D., Banys, J. 2014. Dielectric and magnetic properties of BaTiO3 –NiFe2O4 multiferroic composites. Ceramics International, vol. 40(4), 6165–6170.

Sakanas, A., Grigalaitis, R, Banys, J., Mitoseriu, L., Buscaglia, V., Nanni, P. 2014. Broadband dielectric spectroscopy of BaTiO3-Ni0.5Zn0.5Fe2O4 composite ceramics. Journal of Alloys and Compounds, vol. 602, 241–247.

Dielectric and Ultrasonic Investigations of Composites of Inorganic Nanotubes and Polymers (No MIP-068/2012). Prof. J. Banys, 2012–2014.

The work was devoted for several different types in 2014. First group was related to elastomers embedded with different nanoparticles: polyurea elastomers with inorganic MoS2 nanotubes and Mo6S4I6 nanowires; PDMS elastomer with ZnO nanoparticles. Dielectric and ultrasonic properties were measured in wide temperature range.
Another group of polymer composites were based on piezoelectric polymer polyvinylidene-fluoride (PVDF) which was embedded with ferroelectric barium lead zirconate titanate. Ferroelectric and piezoelectric properties as well as dielectric properties were investigated with Aixacct thick film analyser.
The magnetoelectric composites based on PVDF and embedded with ferrite nanoparticles were investigated by means of broadband dielectric spectroscopy.
The new piezoelectric bent-core main-chain polymers were investigated as potential host matrices for nanoparticles. They were characterised in a wide frequency and temperature ranges.

Main publications:

Belovickis, J., Macutkevic, J., Svirskas, Š., Samulionis, V., Banys, J., Shenderova, O., Borjanovic, V. 2014. Dielectric spectroscopy of polymer based PDMS nanocomposites with ZnO nanoparticles, Ferroelectrics. (accepted in 2014)

Samulionis, V., Svirskas, Š., Banys, J., Sanchez-Ferrer, A., Mrzel, A. Ultrasonic and Dielectric Studies of Polyurea Elastomer Composites with Inorganic Nanoparticles, Ferroelectrics.(accepted in 2014)

Samulionis, V., Svirskas, Š., Banys, J., Sanchez-Ferrer, A., Gimeno, N.,. Ros, M. B. Phase Transitions in Smectic Bent-Core Main-Chain Polymer Networks Detected by Dielectric and Ultrasonic Techniques, Ferroelectrics (accepted in 2014)

Research Council of Lithuania. Taiwan-Latvia-Lithuania Cooperation Project.Materials and Processing Development for Advanced Li Ion Batteries (No TAP-LLT-03/2012).Prof. Habil. Dr. A.F. Orliukas. 2012–2014.

Preparation and characterization of Li4Ti5-xAxO12 (x =0, 0.05, A = Nb, Ta) ceramics.

Main publications:

Orliukas, A. F., Fung, K.-Z., Venckutė, V., Kazlauskienė, V., Miškinis, J., Dindune, A., Kanepe, Z., Ronis, J., Maneikis, A., Šalkus, T., Kežionis, A. 2014. SEM/EDX, XPS and impedance spectroscopy of LiFePO4 and LiFePO4/C ceramics. Lithuanian Journal of Physics, vol. 54(2), 106–113.

Venckutė, V., Kazlauskienė, V., Miškinis, J., Dindune, A., Kanepe, Z., Ronis, J., Maneikis, A., Lelis, M., Jasulaitienė, V., Dobrovolskis, P., Šalkus, T., Kežionis, A., Orliukas, A. F. 2014. Preparation and characterization of solid electrolytes based on TiP2O7 pyrophosphate. Ferroelectrics. (accepted in 2014)

Orliukas, A. F., Fung, K.-Z., Venckutė, V., Kazlauskienė, V., Miškinis, J., Lelis, M. 2014. Structure, surface and broadband impedance spectroscopy of Li4Ti5O12 based ceramics with Nb and Ta. Solid State Ionics. (accepted in 2014)

Research Council of Lithuania. Broadband Spectroscopy of Carbon Nanostructures and FerroelectricRelaxors (VP 1-3.1-ŠMM-07-K-02-041). Dr. J. Macutkevič. 2012–2015.

The dielectric properties of composites filled with various nanocarbons inclusions and ferroelectric relaxors were investigated in very wide frequency range from Hertz to Terahertz. In composites with onion like carbons the lowest pecolation threshold (~6.8% of volume fraction) was observed for smallest size of the aggregates (~40 nm). The value of the dielectric permittivity and the electrical conductivity of the composites with onion like carbon inclusions above the percolation threshold are very high, similar to the values for carbon nanotubes or carbon black composites. A size dependent metal-insulator transition occurs in onion like carbon and polydimethylsiloxane composites. The electrical percolation occurs mainly due to electron tunnelling between nanocarbon inclusions clusters. The electromagnetic and electric properties of the composites above the percolation are mainly governed by electron tunnelling between nanocarbon clusters and electron hopping in quasi-one-dimensional chains inside clusters.
The dielectric properties of relaxors are governed at lower temperatures by polar nanoregions dynamics, while at higher temperatures by electrical conductivity. The temperature dependence of static dielectric permittivity was successfully described by the spherical random bond-random field model. The different freezing temperatures were obtained for the most probable and longest relaxation times due strongly asymmetric distribution of relaxation times at low temperatures.

Main publications:

Macutkevic, J., Kranauskaite, I., Banys, J., Moseenkov, S., Kuznetsov, V., Shenderova, O. 2014. Metal-insulator transition and size dependent electrical percolation in onion-like carbon/polydymethylsiloxane composites. Journal of Applied Physics, vol. 115, 213702.

Palaimiene, E., Macutkevic, J., Banys, J., Kania, A. 2014. Dielectric properties of PMT-PT crystals. Journal of Applied Physics, vol. 116, 104103.

Svirskas S., Ivanov M., Bagdzevicius S., Macutkevic J., Brilingas A., Banys J. 2014.  J. Dec, S. Miga, M. Dunce, E. Birks, M. Antonova, A. Sternberg, Dielectric properties of 0.4Na0.5Bi0.5TiO3-(0.6-x)SrTiO3-xPbTiO3 solid solutions. Acta Materialia, vol. 64, 123–132.

Research Council of Lithuania. Technological Processes of Membranes Production for Micro- Solid Oxide Fuel Cells (No. ATE-09/2012). Project coordinator Prof. S. Tamulevičius (Kaunas University of Technology). Vilnius University Faculty of Physics group leader Dr. T. Šalkus 2012–2014.

The project aims at the development of technological processes of multilayered membrane structures for micro solid oxide fuel cells. New solid electrolytes and thin layer structures are analysed in a wide range of temperatures and frequencies by impedance spectroscopy. The project brings together four teams with complementing experiences in the field of applications for future energy. Three layered membrane structures including electrolyte, positive and negative electrodes have been produced.

Main publications:

Kazlauskas, S., Kežionis, A., Šalkus, T., Orliukas, A. 2014. Charge carrier relaxation in solid VO** conductors. Solid State Ionics, vol. 262, 593–596.

Kazlauskas, S., Kežionis, A., Kazakevičius, E., Orliukas, A.F. 2014.  Charge carrier relaxation and phase transition in scandium stabilized zirconia ceramics. Electrochimica Acta, vol.134, 176–181.

Kezionis, A., Kazlauskas, S., Petrulionis, D., Orliukas, A. F. 2014. Broadband method for the determination of small sample’s electrical and dielectric properties at high temperatures. IEEE Transactions on Microwave Theory and Techniques, vol. 62(10), 2456–2461.

Operational programme for human resources development for 2001-2013 Priority 3 Strengthening Capacities of Researchers VP1-3.1-ŠMM-07-K Support to Research Activities of Scientists and Other Researcher (Global Grant): Rectification by Plasma Waves in 2D Electron Gas and its Application for Terahertz Detection (Nr. VP1-3.1-ŠMM-07-K-03-040). Prof. A. Lisauskas. 2013–2015.

Low frequency noise and responsivity characteristic of CMOS field-effect transistors (that will be used as detectors for fabrication of terahertz camera) investigation has been carried out. Low-noise readout electronics for the array of field-effect transistor based terahertz detectors has been designed and tested.

Main publications:

Zak, A., Bauer, M., Matukas, J., Lisauskas, A., Roskos, H.G., Stake, J. 2014.  Antenna-integrated 0.6 THz FET direct detectors based on CVD graphene. Nano Letters, vol. 14, No. 10, 5834–5838,  doi: 10.1021/nl5027309.

Lisauskas, A., Bauer, M., Boppel, S., Mundt, M., Khamaisi, B., Socher, E., Venckevičius, R., Minkevičius, L., Kašalynas, I., Seliuta, D., Valušis, G., Krozer, V., Roskos, H. G. 2014.  Exploration of terahertz imaging with silicon MOSFETs. J. of Infrared, Millimetre, and Terahertz Waves, vol. 35 (1), 63–80.

Palenskis, V. 2014. Transport of electrons in donor-doped silicon at any degree of degeneracy of electron gas. World Journal of Condensed Matter Physics, vol. 4 (3), 123–133, doi:10.4236/wjcmp.2014.43017

Research project funded from the European Community’s Social Foundation (Grant Agreement No. VP1-3.1-ŠMM-08-K-01-004/KS-120000-1756): Synthesis and Characterization of New Materials for Semiconductor- and Nano-Technologies by Means of Continuous and Ultrafast Spectroscopic Methods. Prof.V. Šablinskas. 2012–2015.

Low frequency noise characteristic investigation of CoFe2O4-BaTiO3 and BaTiO3-NiFe2O4 ceramic composites has been carried out and physical processes during the phase transition were cleared up.
Low frequency noise characteristics of modern optoelectronic devices (light emitting and laser diodes) have been investigated.

Main publications:

Pralgauskaitė, S., Palenskis, V., Matukas, J., Glemža, J., Muliuk, G., Šaulys, B., Trinkūnas, A. 2014. Reliability investigation of light emitting diodes via low frequency noise characteristics, Microelectronics Reliability, http://dx.doi.org/10.1016/.

Research Council of Lithuania. Interactions of Surface and Bulk Acoustic Modes and Applications for Sensors (No. MIP-057/2014). Prof. D. Čiplys. 2014–2015.

This project is dedicated to investigations of high-frequency acoustic waves propagation in solids and layered structures, and to implementation of sensors on the basis of the processes investigated. A propagation of surface acoustic waves (SAW) in nano-layer structures (carbon nanofibers, reduced graphene oxide, vanadium pentoxide xerogel) was investigated.

Main publications:

Čiplys, D., Rimeika, R., Monereo, O., Xuriguera, E., Varea, A., Cirera, A., Shur, M. S. 2014. Sub-second humidity sensing using surface acoustic waves in electrospray-deposited carbon nanofiber and reduced graphene oxide structures. IEEE Sensors Proceedings 2014. Book Series: IEEE Sensors, 110–113.

Sereika, R., Bondarenka, V., Rimeika, R., Sereika, A., Čiplys, D. 2014. Impact of humidity on surface acoustic wave propagation in vanadium pentoxide xerogel-lithium niobate structure. Japanese Journal of Applied Physics, vol. 53 (11), 11804.

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.

Ferroelectrics are ubiquitous materials in modern technology with substantial interest in further extending their functionality in components of medical-diagnostic equipment, microelectronics, energy harvesting, etc. Real ferroelectric materials have internal electric fields due to finite size, charged defects, and in homogeneities in the material. These fields are often considered a hurdle, typically causing degradation of properties. Several recent studies showed strongly enhanced various properties originating from internal fields, hinting that internal fields could be beneficial if properly addressed. This project aims to better understand internal fields in ferroelectrics and use them to obtain enhanced functionality.

Seventh Framework Programme of the European Union, SP3-People, Support for Training and Career Development of Researchers (Marie Curie), FP7 People-2009-IRSES, Grant Agreement No. 247579, NANOLICOM (Nanostructured Lithium Conducting Materials). Prof. Habil. Dr. A. F. Orliukas. 2011–2014.

Elemental compositions and binding energies of Ti 2p, P 2p, O 1s and Li 1s core level of pyrophosphates LiFeP2O7 and Li0.9Fe0.9Ti0.1P2O7 ceramics have been determined by EDX and XPS. Impedance spectroscopy of the ceramics has been performed in the frequency range 10 Hz – 1 MHz by four electrodes method and in frequency range 1 MHz – 3 GHz by microwave impedance spectrometer. The measurements of the electrical properties of the ceramics were carried out in the temperature interval (300 – 700) K.

Main publications:

Venckutė, V., Miškinis, J., Kazlauskienė, V., Šalkus, T., Dindune, A., Kanepe ,Z., Ronis, J., Maneikis, A., Lelis, M., Kežionis, A., Orliukas, A.F. 2014. XRD, XPS, SEM/EDX and broadband impedance spectroscopy study of pyrophospahate LiFeP2O7 and Li0.9Fe0.9Ti0.1P2O7) ceramics, Phase Transitions, vol. 87(5), 438–451.

Venckutė, V., Dindune, A., Kazlauskienė, V., Lelis, M., Jasulaitienė, V., Kežionis, A., Orliukas, A.F. 2014.

Synthesis and investigation of Li4xTi1-xP2O7 pyrophosphates. 11th International Symposium on Systems with Fast Ionic Transport, June 25–29, 2014, Gdansk-Sobieszewo, Poland, 54.

Research Council of Lithuania. Lithuanian–Belarus Partnership Programme for Bilateral Cooperation in the Field of Science and Technologies. Experimental and Theoretical Study of Bulk and Grain Boundary Ionic Transport in Ceramic Lithium and Oxygen Conductors and the Possibilities to Increase their Conductivity (No. TAP LB 04/2013). Dr. T. Šalkus. 2013–2014.

Lithium and oxygen conducting solid electrolytes are being investigated by impedance spectroscopy in the wide frequency range (up to 3 GHz) at different temperatures. The obtained results are used to support theoretical models which describe microscopic processes taking part in the bulk of ceramic grains and their grain boundaries. Deeper understanding of the ionic transport phenomenon could lead to the improvement of ionic conductivity of the studied materials.

Main publications:

Šalkus, T., Šatas, L., Kežionis, A., Kodols, M., Grabis, J., Vikhrenko, V., Gunes, V., Barre, M. 2014. Preparation and investigation of Bi2WO6, Bi2MoO6 and ZnWO4 ceramics, Solid State Ionics. (accepted in 2014)

Vikhrenko, V., Bokun, G., Orliukas, A., Šalkus, T. 2014. Microscopic model of intergrain boundary junction, Procedia Engineering. (accepted in 2014)

Research Council of Lithuania. Lithuanian–French Programme Gilibert for Bilateral Cooperation in the Fields of Culture, Education, Science, Technology and Technique.Synthesis and Characterization of Crystalline and Glassy Lithium Conducting Solid Electrolytes (No. TAP LZ 05/2013). Dr. T. Šalkus. 2013–2014.

Lithium ionic conductors Li0.3La0.57TiO3 and Li1.3Al0.3Ti1.7(PO4)3 were synthesized in the form of glass and crystalline powders. The objective is to mix glassy phase with the crystalline in order to increase grain boundary conductivity of the obtained composite. The main characterization technique is considered to be impedance spectroscopy, which allows one to separate conductivities of different phases of the composites.

Main publications:

Kazakevičius, E., Kežionis, A., Žukauskaitė, L., Barre, M., Šalkus, T., Orliukas, A. 2014. Characterization of NASICON-type Na solid electrolyte ceramics by impedance spectroscopy. Functional Materials Letters, vol. 7 (6), 1440002.

Kazakevičius, E., Kežionis, A., Žukauskaitė, L., Barré, M., Šalkus, T., Žalga, A., Selskis, A., Orliukas, A. 2014. Characterization of Na1.3Al0.3Zr1.7(PO4)3 solid electrolyte ceramics by impedance spectroscopy. Solid State Ionics. (accepted in 2014)

Contractual Research

Investigation of electromagnetic compatibility of LTE with DVB-T and MMDS systems (The Communications Regulatory Authority of the Republic of Lithuania).

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

Rensselaer Polytechnic Institute (USA)
Universitat de Barcelona (Spain)
Goethe University, Frankfurt (Germany)
Lithuanian University of Educational Sciences (Lithuania)
Centre for Physical Sciences and Technology (Lithuania)

OTHER SCIENTIFIC ACTIVITIES

Prof. J. Banys –

Prof. D. Čiplys –

  • co-chair of the organising committee of the 12th School on Acousto-Optics and Applications www.acousto-optics2014.com
  • editor for School Proceedings (to be published in 2015 as a special issue of Acta Physica Polonica A).

Dr. R. Giriūnienė, Dr. R.  Rimeika –

Dr. T. Šalkus –

  • young scientist award by the Lithuanian Academy of Sciences in 2014.

Dr. J. Macutkevič –

 

  • young scientist award by the Lithuanian Academy of Sciences in 2014.

 

DEPARTMENT OF SEMICONDUCTOR PHYSICS

9 Saulėtekio, LT-10222 Vilnius
Tel. 236 6070, fax 236 6070
E-mail

Head – Prof. Habil. Dr. Gintautas Tamulaitis

STAFF

Professors: Habil. Dr. K. Jarašiūnas (part-time), 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. (HP) G. Valušis (part-time), Acad. Habil. Dr. A. Žukauskas (part-time).
Associate professors: Dr. R. Aleksiejūnas (part-time), Dr. R. Butkutė (part-time), Habil. Dr. V. Gavriušinas (part-time), Dr. I. Šimkienė (part-time), Dr. S. Tamošiūnas (part-time), Dr. E. Žąsinas (part-time).
Lecturers: Dr. I. Kašalynas (part-time), Dr. A. Mekys (part-time), A. Arlauskas (part-time).
Research fellows: Dr. J. Storasta (part-time), Dr. V. Kalendra (part-time), Dr. J. Mickevičius, Dr. R. Pūras
Doctoral students: M. Černauskas, K. Gulbinas,  J. Jurkevičius, D. Maželis, D. Meškauskas, K. Nomeika, J. Pavlov, A. Petrulis, Ž. Podlipskas, S. Raišys, I. Reklaitis, V. Rumbauskas, T. Serevičius, M. Skapas, L. Skardžiūtė, D. Ševčenko, A. Tekorius, A. Tuzikas, A. Zabiliūtė.

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
Determination of trace elements using atomic absorption spectrometric, spectrophotometric and kinetic methods

RESEARCH PROJECTS CARRIED OUT IN 2014

Projects Supported by University Budget

Development of Materials, Structures and Devices for Topical Semiconductor Optoelectronics. Prof. K. Jarašiūnas, Prof. S. Juršėnas, Dr. R. Tomašiūnas. 2011–2014.

MOCVD technology for growth of nitrides, their multilayers and nanostructures was built up. GaN, InGaN, AlGaN layers were investigated by scanning electron (EDS, EBIC) and atomic force microscopy, optical (spectroscopy, luminescence, non-linear optical properties) and electrical (mobility) investigation. Orientational properties of materials with noncentrosymmetry (dendrimers, phenylcarbazoles) were investigated. Layered TlGaSe2, InSe and GaSe crystals and 3C-SiC structures were investigated by means of conventional and transient free-carrier absorption spectroscopy, photoacoustic deflection method.

National Research Projects

Research Council of Lithuania. Design and Investigation of Solid State Lighting Based Solar Simulator of a Class Spectrum (No. MIP-099/2012). Prof. V. Tamošiūnas. 2012–2014.

During the Project several designs of AAA class solar simulators for solar cell testing were demonstrated employing high power light emitting diodes (LEDs): modular simulator based on surface mounted LEDs; hybrid simulator with improved spectral match; compact simulator with only 19 LEDs.

Main publications:

Novičkovas A., Baguckis A., Vaitkūnas A., Mekys A., Tamošiūnas V. 2014. Investigation of solar simulator based on high-power light-emitting diodes.  Lith. J. of Phys., vol. 54, 114–119.

Tamošiūnas V., Novičkovas A., Vaitkūnas A., Mekys A. 2013. Investigation of compact solar simulator based on high power light emitting diodes. Proceedings of 28th European Photovoltaic Solar Energy Conference and Exhibition, 206–208.

Baguckis A., Novičkovas A., Mekys A., Balakauskas S., Tamošiūnas V. 2014. Comparison of Xenon Arc Lamp Based and Light Emitting Diode Based Solar Simulators. Proceedings of 29th European Photovoltaic Solar Energy Conference and Exhibition, 120–122.

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 –

Prof. A. Žukauskas –

 member of the Lithuanian Academy of Sciences, http://www.lma.lt.

 

DEPARTMENT OF SOLID STATE ELECTRONICS

9 Saulėtekio, LT-10222 Vilnius
Tel. 236 6045, fax 236 6003
E-mail:

Head - Prof. Dr. Kęstutis Arlauskas

STAFF

Professors: Dr. K. Arlauskas, Habil. Dr. P. J. Žilinskas.
Associate professors: Dr. M. Viliūnas, Dr. A.Poškus, Dr. A. Pažėra, Dr. V. Jankauskas (part time), Dr. R. Maldžius (part time), Dr. G. Sliaužys (part time).
Research fellows: Habil. Dr. G. Juška, Habil. Dr. T. Lozovski, Habil. Dr. V. Gaidelis, Dr. K. Genevičius, Dr. N. Nekrašas, Dr. G. Sliaužys (part time), Dr. R. Purlys, Dr. R. Rinkūnas, Dr. V. Jankauskas (part time), Dr. R. Maldžius (part time).
Doctoral students: S .Meera, B. Lenkevičiūtė, R. Dobužinskas, J. Važgėla.

RESEARCH INTERESTS

New functional materials and structures

RESEARCH PROJECTS CARRIED OUT IN 2014

Projects Supported by University Budget

The Research of Charge Carrier Dynamics in Disordered Materials for Devices Applications.  Prof. K.Arlauskas.2013–2016.

The theoretical and experimental investigation of the current transients in organic field effect transistors (FET) for evaluation of differences of charge carrier mobility along and across of channel of FET whose values were estimated by classical stationary current method and current transient measurements.
Crosslinking studies in double phenylcarbazole epoxycompouds in order to find the optimal method for crosslinking technology with best charge transfer were carried out. Realization of anthracene-based deep-blue emitters exhibiting high fluorescence efficiency and demonstrating good film forming properties and high carrier drift mobility was investigated.
The experimental investigation of electric and dielectric parameters in newly synthesized organic material for possible photovoltaic and OLED applications.
The following investigations were performed: of the influence of alternating electrical field to x-rays diffraction spectra in quartz; of the electro spinning using solution of the polymers and development of theoretical model.
Development of the Monte Carlo simulations code for calculations of the interactions between high energy electrons and photons with material, calculations of the mean energy loss for creating one pair of ions in inert gas were done.

Patent (Lithuania)

Purlys R., Janavičius A. J., Balandin V., Viliūnas M., Balakauskas S., Poškus A. New method and its application for defects formation by using x-rays and electrical field, Department of Solid State Electronics, LT2012094A.

Main publications:

Poškus A. 2014. Monte Carlo estimation of average energy required to produce an ion pair in noble gases by electrons with energies from 1 keV to 100 MeV. Journal of Nuclear Science and Technology, [Published online: 04 Nov 2014, link: http://dx.doi.org/10.1080/00223131.2014.974710].

Kukhta N., Simokaitiene J., Volyniuk D., Ostrauskaite J., Gražulevicius J., Juška G., Jankauskas V. 2014. Effect of linking topology on the properties of star-shaped derivatives of triazine and fluorene. Synthetic Metals, vol. 195, 266–275.

Serevičius T., Komskis R., Adomėnas P., Adomėnienė O., Jankauskas V., Gruodis A., Kazlauskas K., Juršėnas S. 2014. Non-symmetric 9,10-diphenylanthracene-based deep-blue emitters with enhanced charge transport properties. Physical Chemistry Chemical Physics, vol. 16, 7089–7101.

National Research Projects

Research Council of Lithuania. Influence of Nano-Morphology on Charge Carrier Dynamics (VP1-3.1-ŠMM-07-K-01-023). Prof. G. Juška. 2011–2015.

This project focuses on charge carriers transport and related phenomena (efficiency of photo-generation, mobility of the charge carriers, recombination, trapping and etc.) in nanostructured organic materials for improving performance of Solar cells and field effect transistors.

Main publications:

Juška G., Nekrašas N., Genevičius K., Grigaitis T. 2014. The determination of charge carrier mobility from the current transients in organic field effect transistor. J. Appl. Phys., vol. 116, 023702.

Armin A., Juška G., Ullah M., Velusamy M., Burn P., Meredith P., Pivrikas A. 2014. Balanced carrier mobilities: not a necessary condition for high-efficiency thin organic solar cells as determined by MIS-CELIV. Adv.Energy Mater, vol. 4, 1300954.

Philippa B., Stolterfoht M., Burn P., Juška G., Meredith P., White R., Pivrikas A. 2014. The impact of hot charge carrier mobility on photocurrent losses in polymer-based solar cells. Scientific Reports, vol. 4, 5695.

International Research Projects

FP7 ITN Marie-Curie. Ensuring Stability in Organic Solar Cells – ESTABLIS. 2011–2015.

This project will train 4 postdocs and 11 PhD students to develop the materials and techniques required to give cheap organic solar cells 10 year stabilities. Scientific objectives are: production materials with increased stabilities, clarification of photo(chemical) and mechanical degradation pathways, manufacturing organic solar cells with reduced inter-layer contaminations and increased inter-facial adhesion. Industrials partners: Belectric, Heraeus, Merck.

Main publications:

Stephen M., Karuthedath S., Sauermann T., Genevičius K., Juška G. 2014. Degradation effects on charge carrier transport in P3HT:PCBM solar cells studied by photo-CELIV and ToF.  Proc. of SPIE, vol. 9184, 918424.

Contractual Research

Consulting Agreement. Stora Enso Oyj, Helsinky, Finland, 2010–2014.
R&D Consulting Services Agreement. BASF Schweiz AG, Switzerland, 2014.
Consulting Agreement. Lappeenranta University of Technology, Finland, 2011–2014.

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

School of Chemistry and Molecular Biosciences, Centre For Organic Photonics and Electronics (COPE), University of Queensland (Australia)
Thunder Bay Research Institute, Thunder Bay (Canada)

OTHER SCIENTIFIC ACTIVITIES

Prof. G. Juška -

  • editorial board member of 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
Associate professors: Doc. Dr. J. Bučinskas, Doc. Dr. J. Šulskus, Doc. Dr. K. Glemža, Dr. T. Gajdosik, Dr. G.Trinkūnas.
Lecturers: Dr. O. Rancova, Dr. M. Mačernis, Dr. V. Balevičius, Dr. S. Toliautas.
Research fellows: Junior scientific researcher J. Meldaikis.
Doctoral students: V. Butkus, J. Chmeliov, S.Malickaja, V. Abramavičius, A. Gelžinis, V. Chorošajev, V. Dūdėnas, A. Stepšys.

Processes Modelling Laboratory at the Department of Theoretical Physics

Head – Dr. Mindaugas Mačernis.

RESEARCH INTERESTS

Development of exciton theory and its application to the nonlinear spectroscopy of molecular complexes

Excitation dynamics in complex molecular systems and nanostructures
Coherent control and optimization of nonlinear optical signals of bio molecules and nano-systems
Development of the theoretical background of multi-dimensional spectra of molecular complexes
Modelling of single molecular spectra of complex systems                                           
Development of quantum mechanics and quantum electrodynamics for characterization of transitions in atoms, molecules and molecular complexes 
Application of high performance parallel computing in theoretical modelling of processes in photoactive organic materials and nanosystems
Models of radiative neutrino masses

RESEARCH PROJECTS CARRIED OUT IN 2014

Project Supported by University Budget

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

A simple conceptual model describing excitation diffusion in a continuous medium and accounting for possible variations of the excitation transfer rates was proposed. The model is also able to provide valuable information about the structural and functional organization of the photosynthetic antenna and in a straightforward way solves various contradictions currently existing in the literature. Analysis of the experimental data of the fluorescence induction in photosystem II at different external conditions provides the possibility to determine the rate and the efficiency of the self-regulation ability in the antenna complexes.
The study of the excited states in PBMSi investigated by performing quantum-mechanical calculations of the model compound and comparison with experimental investigation results suggests a new molecular-level engineering approach for enhancement of the inter system crossing.

Main publications:

Chmeliov, J., Trinkūnas, G., van Amerongen, H., Valkūnas, L. 2014. Light harvesting in a fluctuating antenna. Journal of the American Chemical Society, vol. 136, 8963–8972.

Belgio, E., Kapitonova, E., Chmeliov, J., Duffy, C. D. P., Ungerer, P., Valkunas, L., Ruban, A. V. 2014. Economic photoprotection in photosystem II that retains a complete light-harvesting system with slow energy traps. Nature Communication, vol. 5, 4433.

Kadashchuk, A., Skryshevski, Y., Vakhnin, A., Toliautas, S.,  Šulskus, J., Augulis, R. , Gulbinas, V., Nešpurek, S. , Genoe, J. , Valkūnas, L. 2014. Highly efficient intrinsic phosphorescence from a σ-conjugated poly(silylene) polymer. The Journal of Physical Chemistry C: Nanomaterials, Interfaces and Hard Matter, vol., 118, 22923–22934.

National Research Projects

Research Council of Lithuania. Modelling and Control of Exciton Quantum Dynamics in Nanostructures (No: VP1-3.1-ŠMM-07-K-01-020). Prof. D. Abramavičius 2012–2015

Research resulted in two publications. First, the optical properties of carbon nanotubes have been revisited. Creation of several excitons in a nanotube results in their scattering and nonlinear dissipation. The coherent and dissipative processes have been theoretically described and compared experiments. Second, a coherent two dimensional spectra of a biological molecular aggregate LH2 has been theoretically studied and its static disorder and dynamic fluctuations have been characterized. The temperature dependence implied disharmonic nature of protein fluctuations. 

Main publications:

Valkunas, L., Abramavicius, D., 2014. Coherent excitons in carbon nanotubes. In Mohseni, M., Omar, Y., Engel, G., Plenio, M. B. (eds). Quantum Effects in Biology, Cambridge Univ. Press. 335–349

Rancova, O., Abramavicius, D. 2014. Static and dynamic disorder in bacterial light-harvesting complex LH2: a 2DES simulation stud.  J. Phys. Chem. B, vol. 118, 7533–7540.

Research Council of Lithuania. Nonequilibrium Photo-Induced Processes in Molecular Aggregates (No: MIP-069/2012). Prof. D. Abramavičius. 2013–2015

Research yielded four publications. Optically excited stochastic excitation dynamics in model systems has been described by stochastic Schroedinger equation. Coherent vibrations have small influence when they weakly couple to electronic excitations, however, they still may lead to excitonic polaron formation. Stronger coupling results in mixing of electronic and nuclear degrees of freedom. Application of the electro-vibrational mixing theory allowed explaining excitation dynamics in photosynthetic PS-II reaction centre.

Main publications:

Abramavicius, V., Abramavicius, D. 2014. Excitation transfer pathways in excitonic aggregates revealed by the stochastic Schrodinger equation. J. Chem. Phys., vol. 140, 065103.

Chorosajev, V., Gelzinis, A., Valkunas, L., Abramavicius, D. 2014. Dynamics of exciton-polaron transition in molecular assemblies: The variational approach. J. Chem. Phys., vol. 140, 244108.

Fuller, F. D., Pan, J., Gelzinis, A., Butkus, V., Senlik, S. S., Wilcox, D. E., Yocum, C. F, Valkunas, L., Abramavicius, D., Ogilvie, J. P. 2014. Vibronic coherence in oxygenic photosynthesis. Nature Chem., vol.6, 706–711.

Baltic-German University Liaison Office. Theoretical Particle Physics: Connecting the Seesaw Mechanism for  Neutrinos with an Extended Higgs Sector. (No: BS-120000-1524). Assoc. Prof. T. Gajdosik. 2014/07–12.

The project financed seminars and visits and started the research on radiative Neutrino masses and their connection to particle physics experiments.

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)

Other scientific activities

Prof. L. Valkūnas –

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

Prof. K. Pyragas –

Prof. D. Abramavičius –

  • member of the American Physical Society.

Assoc. Prof. T. Gajdosik -

 member of the Austrian Physical Society.