Category: news

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Coexistence of Bloch and Parametric Mechanisms of High-Frequency Gain in Doped Superlattices

New open access article is published in the journal Nanomaterials (MDPI) by Vladislovas Čižas, Natalia Alexeeva, Kirill N. Alekseev and Gintaras Valušis. Theoretical study dives into the physical mechanisms of high-frequency gain in a doped semiconductor superlattice

The findings of the research contributes to the advancement of new miniature GHz–THz frequency generators, amplifiers, and dividers operating at room temperature.

The research was partially funded by the Marius Jakulis Jason Foundation and the Research Council of Lithuania (No 01.2.2-LMT-K-718-03-0096).

The paper can be reached through this DOI: . https://doi.org/10.3390/nano13131993

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Electro-optical modulation of terahertz beam by drifting space-charge domains in n-GaN epilayers

The research article by Roman B. Balagula, Liudvikas Subačius, Paweł Prystawko, and Irmantas Kašalynas is published in Journal of Applied Physics, AIP Publishing. The work entitled “Electro-optical modulation of terahertz beam by drifting space-charge domains in n-GaN epilayers” investigates the transmission modulation of THz field in GaN semiconductor as a response to space-charge domains under near-to-breakdown electrical field conditions.

Traces of charge current density j, the electro-optic modulation of THz beam transmission ΔTeo, and the sample specific resistance, Edc/j, found as a ratio between measurements of applied electric field and current density traces.

The open access research article is available through https://doi.org/10.1063/5.0152661

The work was supported by the Research Council of Lithuania through the “Hybrid plasmonic components for THz range (T-HP)” Project (Grant No. DOTSUT-184) funded by the European Regional Development Fund according to the supported activity “Research Projects Implemented by World-class Researcher Groups” under the Measure No. 01.2.2-LMT-K-718-03-0096. The work at Warsaw was supported by the National Center for Research and Development (Grant No. TECHMATSTRATEG-III/0003/2019/EnerGaN).

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Narrowband Thermal Terahertz Emission of Ti/Au Metasurface on Homoepitaxial GaAs

New work by I. Grigelionis et al. was published in the scientific journal Sensors from MDPI publisher. Authors report on the experimental evidence of thermal terahertz emission tailored by magnetic polariton excitations in entirely GaAs-based structures equipped with metasurfaces. Thermal emission was measured at 390 C temperature in the range from 0.7 THz to 1.3 THz, depending on the size of the square metacells.

The magnetic polariton resonance quality factors obtained at elevated temperatures (Q ~ 3.3 to 5.2) are very similar to those of MIM structures as well as to 2D plasmon resonance quality at cryogenic temperatures.

The open access paper can be reached through https://doi.org/10.3390/s23104600

This research has received funding from the Research Council of Lithuania (LMTLT), agreement No. S-MIP-22-76.

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The 2023 terahertz science and technology roadmap

New roadmap for THz science and technology is just published in the Journal of Physics D: Applied Physics by IOP Publishing. Among the number of distinguished authors one can find Gintaras Valušis who have significantly contributed to the publication. Congratulations!

The roadmap is a collection of sections addressing the particular aspects of latest THz technology developments. It is indeed the excellent source to get the insights to the future of THz science.

The publication under open access license can be accessed trough this DOI: https://doi.org/10.1088/1361-6463/acbe4c

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How Lithuanian semiconductor creators impressed colleagues from Taiwan

EN: In the “Curiosity Gene” episode the significance and future of semiconductor technologies in Lithuania in the new light of Taiwan transfer of transistor manufacture secrets to Lithuania is presented. The head of FTMC prof. Gintaras Valušis and senior research fellow dr. Linas Minkevičius talks straight from THz Photonics Lab of FTMC. The episode in Lithuanian language can be accessed through this link to the archives of national broadcaster LRT.

LT: “Smalsumo genas” laidoje pasakojama apie puslaidininkinių technologijų svarbą ir perspektyvas Lietuvoje, Taivanui perleidžiant tranzistorių gamybos paslaptis. Laidoje iš Terahercų fotonikos laboratorijos kalba FTMC direktorius prof. Gintaras Valušis ir mokslininkas dr. Linas Minkevičius. Laidos įrašą kviečiame pažiūrėti paspaudus šią nuorodą į LRT mediateką.


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European patent on the method for fabrication of recessed electrical elements (EP3975224) is published by EPO

European Patent Office (EPO) just published the patent for the method for fabrication of recessed electrical elements (EP3975224) by inventors Irmantas Kašalynas (head of our lab), Simonas Indrašiūnas, Pawel Prystawko, and Piotr Kruszewski. Two later inventors are our collaborators from Institute of High Pressure Physics at Polish
Academy of Sciences, Poland. The patent can be accessed here: https://register.epo.org/application?number=EP21183785

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New paper about structured THz radiation: Imaging with Airy beam

New paper by Rusnė Ivaškevičiūtė-Povilauskienė et. al just published in Light Science and Applications journal by Nature publishing group entitled ”Terahertz structured light: nonparaxial Airy imaging using silicon diffractive optics”. The work demonstrates the structured nonparaxial THz light in the form of Airy, Bessel, and Gaussian beams generated in a compact way using exclusively silicon diffractive optics prepared by femtosecond laser ablation technology. The structured THz light consistently outperforms the conventional one in resolution and contrast.

The findings open new frontiers of structured light applications in imaging and inverse scattering problems. Imaging of stacked graphene layers with THz Airy beam revealed potential to be applied for inspection of 2D materials quality.

The article is freely available under Open Access license and can be reached through the DOI address: https://doi.org/10.1038/s41377-022-01007-z


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International Workshop on Nitride Semiconductors (IWN)

Head of laboratory Dr. Irmantas Kašalynas and PhD student Justinas Jorudas represented THz Photonics laboratory at International Workshop on Nitride Semiconductors (IWN) which took place in Berlin, Germany from 10th till 14th of October. Our lab presented scientific results in 1 oral and 3 poster presentations.

Head of laboratory Dr. Irmantas Kašalynas gives a talk at IWN meeting,

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New study on formation and drift of space-charge domains with velocity of sound in n-type GaN

New paper by Roman Balagula et al. under the title ”Space-charge domains in n-type GaN epilayers under pulsed electric field” is published in the Applied Physics Letters.

The experimental work investigates the formation and drift of space-charge domains with velocity of sound in n-type GaN. The findings defines the constraints
for the design of GaN-based power electronic devices.

The paper can be reached through this DOI: https://doi.org/10.1063/5.0098951

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THz Atelier participates at the IRMMW-THz 2022 conference in Delft, the Netherlands

From 28th of August till 2nd of September the THz Photonics laboratory is going to the 47th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz)! Our all lab is going to take part in this massive scientific event. This year we discuss very interesting scientific results in 4 oral and 6 poster presentations (10 papers in total). Let’s meet there: https://www.irmmw-thz2022.tudelft.nl/program.html