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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.

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.

Seniutinas G.,Swinburne University of Technology | Seniutinas G.,Australian National Fabrication Facility | Gervinskas G.,Swinburne University of Technology | Gervinskas G.,Australian National Fabrication Facility | And 7 more authors.
Applied Physics A | Year: 2014

A terahertz (THz) photomixer: (i) a meander type antenna with integrated nanoelectrodes on (ii) a low temperature grown GaAs has been fabricated and characterized. It was designed for spectral range of 0.3-0.4 THz where molecular fingerprinting and sensing are performed. By combination of electron beam lithography with post-processing using focused ion beam (FIB), milling the THz emitter was successfully fabricated. Nanogaps as small as 40 nm width in the active area of photomixer were milled by FIB. Nanocontacts enhance electric fields of the illuminated and THz radiation and contribute to a better collection of photo-electrons. THz emission was obtained and spectrally characterized. © 2014 Springer-Verlag Berlin Heidelberg.

Adamonis J.,Lithuanian Academy of Sciences | Adamonis J.,TERAVIL Ltd | 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.

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.

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