TERAVIL Ltd

Vilnius, Lithuania

TERAVIL Ltd

Vilnius, Lithuania

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Gaborit G.,CNRS Institute for Microelectronics, Electromagnetism, and Photonics: Hyperfrequency and Characterization lab | Biciunas A.,Lithuanian Academy of Sciences | Biciunas A.,Teravil Ltd. | Bernier M.,CNRS Institute for Microelectronics, Electromagnetism, and Photonics: Hyperfrequency and Characterization lab | Coutaz J.-L.,CNRS Institute for Microelectronics, Electromagnetism, and Photonics: Hyperfrequency and Characterization lab
IEEE Transactions on Terahertz Science and Technology | Year: 2015

Based on optical rectification in a ZnTe crystal, a vectorial terahertz (THz) emitter is here theoretically and experimentally demonstrated. The use of the particular orientation 111 leads to a polarization state angle tunable THz source. This configuration requires only an optical wave plate to manage the impinging optical polarization state, thus adjusting the transverse THz electric field orientation. Moreover, the optical rectification efficiency as well as the THz signal bandwidth remain constant from horizontal to vertical Terahertz polarization. The same crystal, acting then like a THz receiver, allows to perform the vectorial analysis of a THz pulse. © 2011-2012 IEEE.


Leyman R.R.,University of Strathclyde | Gorodetsky A.,Aston University | Gorodetsky A.,Saint Petersburg State University of Information Technologies, Mechanics and Optics | Bazieva N.,Aston University | And 5 more authors.
Laser and Photonics Reviews | Year: 2016

Compact and tunable semiconductor terahertz sources providing direct electrical control, efficient operation at room temperatures and device integration opportunities are of great interest at the present time. One of the most well-established techniques for terahertz generation utilises photoconductive antennas driven by ultrafast pulsed or dual-wavelength continuous wave laser systems, though some limitations, such as confined optical wavelength pumping range and thermal breakdown, still exist. The use of quantum dot-based semiconductor materials, having unique carrier dynamics and material properties, can help to overcome limitations and enable efficient optical-to-terahertz signal conversion at room temperatures. Here we discuss the construction of novel and versatile terahertz transceiver systems based on quantum dot semiconductor devices. Configurable, energy-dependent optical and electronic characteristics of quantum-dot-based semiconductors are described, and the resonant response to optical pump wavelength is revealed. Terahertz signal generation and detection at energies that resonantly excite only the implanted quantum dots opens the potential for using compact quantum dot-based semiconductor lasers as pump sources. Proof-of-concept experiments are demonstrated here that show quantum dot-based samples to have higher optical pump damage thresholds and reduced carrier lifetime with increasing pump power. (Figure presented.). © 2016 by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


Wahaia F.,University of Porto | Kasalynas I.,Terahertz Photonics | Seliuta D.,Terahertz Photonics | Molis G.,TERAVIL Ltd | And 8 more authors.
Journal of Molecular Structure | Year: 2015

In this work, samples of non-neoplastic and adenocarcinoma-affected human colon tissue samples were analyzed using multipoint transmission time-domain THz spectroscopy (THz-TDS) to sort out the contrast-contributing factors other than water, the main contrast mechanism factor in in-vivo or in freshly excised bio-tissue. Solving the electromagnetic inverse problem through THz-TDS and, analyzing the transmittance spectra that yielded the frequency-dependent absorption coefficient α and refractive index n of non-neoplastic and neoplastic tissues, we show that it is possible to distinguish between non-neoplastic and neoplastic regions in paraffin-embedded dehydrated. Results and discussion are presented. © 2014 Elsevier B.V. All rights reserved.


Wahaia F.,University of Porto | Kasalynas I.,Terahertz Photonics | Seliuta D.,Terahertz Photonics | Molis G.,TERAVIL Ltd | And 8 more authors.
Journal of Molecular Structure | Year: 2015

Terahertz (THz) spectroscopy constitute promising technique for biomedical applications as a complementary and powerful tool for diseases screening specially for early cancer diagnostic. The THz radiation is not harmful to biological tissues. As increased blood supply in cancer-affected tissues and consequent local increase in tissue water content makes THz technology a potentially attractive. In the present work, samples of healthy and adenocarcinoma-affected gastric tissue were analyzed using transmission time-domain THz spectroscopy (THz-TDS). The work shows the capability of the technique to distinguish between normal and cancerous regions in dried and paraffin-embedded samples. Plots of absorption coefficient α and refractive index n of normal and cancer affected tissues, are presented and the conditions for discrimination between normal and affected tissues are discussed. © 2014 Elsevier B.V. All rights reserved.


Wahaia F.,University of Porto | Kasalynas I.,Terahertz Photonics | Seliuta D.,Terahertz Photonics | Molis G.,TERAVIL Ltd | And 8 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

In the present work, samples of healthy and adenocarcinoma-affected human gastric tissue were analyzed using transmission time-domain THz spectroscopy (THz-TDS) and spectroscopic THz imaging at 201 and 590 GHz. The work shows that it is possible to distinguish between normal and cancerous regions in dried and paraffin-embedded samples. Plots of absorption coefficient and refractive index n of normal and cancer affected tissues, as well as 2-D transmission THz images are presented and the conditions for discrimination between normal and affected tissues are discussed. © 2014 SPIE.


Leyman R.,University of Dundee | Carnegie D.,University of Dundee | Bazieva N.,University of Dundee | Molis G.,Teravil Ltd | And 6 more authors.
2013 IEEE Photonics Conference, IPC 2013 | Year: 2013

The THz optoelectronics field is now beginning to mature and semiconductor-based THz signal emitter/detector devices are becoming more widely implemented as analytical tools in spectroscopy and imaging1. The predominant area of development in this field has always been the photoconductive (PC) active material which forms the basis of the necessary ultrafast switching process. These materials traditionally are optically pumped using, for example, a Ti:Sapphire laser which can generate ultrashort pulses with photonic energy higher than the active material bandgap. This allows the generation of (photo)carrier pairs which are accelerated by the E-field of an integrated antenna electrode pair and then captured over ultrashort timescales (τc < 1ps) usually by defects and trapping sites throughout the active material lattice. As a defective material (such as low-temperature-grown GaAs, 'LT-GaAs') is typically used, many parameters such as carrier mobility and PC gain are greatly compromised. It has been shown previously that quantum dots (QDs) deposited within or over GaAs can enable and/or enhance the efficiency of THz signal generation2. We demonstrate here the efficient generation of THz output signals using PC THz antennas based on semiconductor structures comprised of InAs quantum dots (QDs) embedded in high quality crystalline GaAs, whereby the embedded QDs act as the ultrafast capture mechanism3. © 2013 IEEE.


Minkevicius L.,Lithuanian Academy of Sciences | Suzanoviciene R.,Lithuanian Academy of Sciences | Balakauskas S.,Lithuanian Academy of Sciences | Molis G.,TeraVil Ltd | And 5 more authors.
Electronics Letters | Year: 2012

Terahertz time-domain spectroscopy was applied to measure the reflectivity spectra of a silicon solar cell with tab wire soldering defects. It was demonstrated that THz phase imaging data allows a reliable estimation of height differences of bulging tab wires within 22 as tested for 0.63 and 1.07mm loop peaks. Such measurements can be implemented for automated defect correction in future solar module production lines. © 2012 The Institution of Engineering and Technology.


Adamonis J.,Lithuanian Academy of Sciences | Adamonis J.,Ltd. Teravil | Rusteika N.,Lithuanian Academy of Sciences | Rusteika N.,Ekspla Ltd. | And 3 more authors.
Optics Communications | Year: 2013

In this work we propose a compact, easily tunable terahertz burst generation system based on the mixing of two linearly chirped optical pulses in the Michelson interferometer. The use of linearly chirped optical pulses ejected straight from the fiber laser enabled us to avoid bulky external optical pulse stretching schemes. Even for non-compensated third and higher order dispersion that is taking place in the optical fiber terahertz bursts of relatively narrow bandwidth of 55 GHz were registered. The system operation range determined from the power measurements reached 2 THz. © 2012 Elsevier B.V. All rights reserved.


Molis G.,Teravil Ltd | Arlauskas A.,Lithuanian Academy of Sciences | Krotkus A.,Lithuanian Academy of Sciences | Leyman R.,University of Dundee | And 2 more authors.
International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz | Year: 2012

Surface THz pulse emission from samples containing 40 layers of InAs quantum dots grown on a AlAs/GaAs Bragg reflector as well as the picosecond photoconductivity of devices manufactured from this material was investigated as a function of the optical wavelength of femtosecond pulses generated by an optical parametric amplifier. © 2012 IEEE.


Beleckaite L.,Lithuanian Academy of Sciences | Molis G.,Lithuanian Academy of Sciences | Molis G.,Teravil Ltd. | Adomavicius R.,Lithuanian Academy of Sciences | And 5 more authors.
IRMMW-THz 2015 - 40th International Conference on Infrared, Millimeter, and Terahertz Waves | Year: 2015

In this work THz emission of the non-vertically aligned GaMnAs and InGaAs nanowires (NWs) were investigated for the first time. THz emission azimuthal dependencies on different nanowire layers were measured. In addition THz pulse amplitude dependencies on an angle between the incident laser beam and a normal to the sample surface were accomplished for the removed NW layer. The investigated layers can be used in rotating polarization THz emitters. This application is very important because the principle of half wave plate cannot be used due to a wide spectrum of the THz pulses. © 2015 IEEE.

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