Abstract-Observation of terahertz-induced magnetooscillations in graphene

Erwin Mönch, Denis A. Bandurin, Ivan A. Dmitriev, Isabelle Y. Phinney, Ivan Yahniuk, Takashi Taniguchi, Kenji Watanabe, Pablo Jarillo-Herrero, Sergey D. Ganichev

https://pubs.acs.org/doi/pdf/10.1021/acs.nanolett.0c01918#

When high-frequency radiation is incident upon graphene subjected to a perpendicular magnetic field, graphene absorbs incident photons by allowing transitions between nearest LLs that follow strict selection rules dictated by angular momentum conservation. Here we show a qualitative deviation from this behavior in high-quality graphene devices exposed to terahertz (THz) radiation. We demonstrate the emergence of a pronounced THz-driven photoresponse, which exhibits low-field magnetooscillations governed by the ratio of the frequency of the incoming radiation and the quasiclassical cyclotron frequency. We analyze the modifications of generated photovoltage with the radiation frequency and carrier density and demonstrate that the observed photoresponse shares a common origin with microwave-induced resistance oscillations previously observed in GaAs-based heterostructures, yet in graphene, it appears at much higher frequencies and persists above liquid nitrogen temperatures. Our observations expand the family of radiation-driven phenomena in graphene, paving the way for future studies of nonequilibrium electron transport.

Abstract-Observation of terahertz-induced magnetooscillations in graphene

Erwin Mönch, Denis A. Bandurin, Ivan A. Dmitriev, Isabelle Y. Phinney, Ivan Yahniuk, Takashi Taniguchi, Kenji Watanabe, Pablo Jarillo-Herrero, Sergey D. Ganichev

https://arxiv.org/abs/2005.01118

When high-frequency radiation is incident upon graphene subjected to a perpendicular magnetic field, graphene absorbs incident photons by allowing transitions between nearest LLs that follow strict selection rules dictated by angular momentum conservation. Here we show a qualitative deviation from this behavior in high-quality graphene devices exposed to terahertz (THz) radiation. We demonstrate the emergence of a pronounced THz-driven photoresponse, which exhibits low-field magnetooscillations governed by the ratio of the frequency of the incoming radiation and the quasiclassical cyclotron frequency. We analyze the modifications of generated photovoltage with the radiation frequency and carrier density and demonstrate that the observed photoresponse shares a common origin with microwave-induced resistance oscillations previously observed in GaAs-based heterostructures, yet in graphene, it appears at much higher frequencies and persists above liquid nitrogen temperatures. Our observations expand the family of radiation-driven phenomena in graphene and offer potential for the development of novel optoelectronic devices.

Abstract-Terahertz 3D printed diffractive lens matrices for field-effect transistor detector focal plane arrays

Krzesimir Szkudlarek, Maciej Sypek, Grzegorz Cywiński, Jarosław Suszek, Przemysław Zagrajek, Anna Feduniewicz-Żmuda, Ivan Yahniuk, Sergey Yatsunenko, Anna Nowakowska-Siwińska, Dominique Coquillat, Dmytro B. But, Martyna Rachoń, Karolina Węgrzyńska, Czesław Skierbiszewski, and Wojciech Knap
https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-18-20119

We present the concept, the fabrication processes and the experimental results for materials and optics that can be used for terahertz field-effect transistor detector focal plane arrays. More specifically, we propose 3D printed arrays of a new type – diffractive multi-zone lenses of which the performance is superior to that of previously used mono-zone diffractive or refractive elements and evaluate them with GaN/AlGaN field-effect transistor terahertz detectors. Experiments performed in the 300-GHz atmospheric window show that the lens arrays offer both a good efficiency and good uniformity, and may improve the signal-to-noise ratio of the terahertz field-effect transistor detectors by more than one order of magnitude. In practice, we tested 3 × 12 lens linear arrays with printed circuit board THz detector arrays used in postal security scanners and observed significant signal-to-noise improvements. Our results clearly show that the proposed technology provides a way to produce cost-effective, reproducible, flat optics for large-size field-effect transistor THz-detector focal plane arrays.

© 2016 Optical Society of America

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