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Your search keyword '"Nadzeya Valynets"' showing total 2 results
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2 results on '"Nadzeya Valynets"'

1. Terahertz Absorber with Graphene Enhanced Polymer Hemispheres Array

Author

Alesia Paddubskaya, Nadzeya Valynets, Sergey Maksimenko, Mukesh Kumar, Marian Baah, Markku Pekkarinen, Yuri Svirko, Gintaras Valušis, and Polina Kuzhir

Subjects
graphene, metasurface, terahertz, absorption, electromagnetic wave, Chemistry, QD1-999
Abstract

We propose an original technique for the fabrication of terahertz (THz) metasurfaces comprising a 3D printed regular array of polymer hemispheres covered with a thin conductive layer. We demonstrate that the deposition of a thin metal layer onto polymer hemispheres suppresses the THz reflectivity to almost zero, while the frequency range of such a suppression can be considerably broadened by enhancing the structure with graphene. Scaling up of the proposed technique makes it possible to tailor the electromagnetic responses of metasurfaces and allows for the fabrication of various components of THz photonics.

Published
2021
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2. The Performance of Graphene-Enhanced THz Grating: Impact of the Gold Layer Imperfectness

Author

Patrizia Lamberti, Monica La Mura, Vincenzo Tucci, Erick Nkyalu, Ali Khan, Marina Yakovleva, Nadzeya Valynets, Alesia Paddubskaya, Aleksandr Saushin, Viatcheslav Vanyukov, Marian Baah, Andrzej Urbanowicz, Yuri Svirko, and Polina Kuzhir

Subjects
Technology, Microscopy, QC120-168.85, QH201-278.5, FEM model, THz time domain spectroscopy, Fabry–Pérot resonances, Drude–Smith model, gold non-ideality, graphene, multilayer device, Engineering (General). Civil engineering (General), TK1-9971, Gold non‐ideality, Multilayer device, Descriptive and experimental mechanics, General Materials Science, Electrical engineering. Electronics. Nuclear engineering, TA1-2040, Graphene
Abstract

We report the performance of a graphene-enhanced THz grating fabricated by depositing a gold layer on the femtosecond micromachined SiO2 substrate. The morphology of the gold plated patterned substrate was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM), while the quality of the chemical vapor deposition (CVD) graphene was evaluated by Raman spectroscopy. The electromagnetic (EM) response of the metasurface comprising the graphene sheet and the gold plated substrate was studied by THz time domain spectroscopy in the 100 GHz–1 THz frequency range. We employed the finite elements method (FEM) to model the metasurface EM response by adjusting the ac conductivity of the gold layer covering the patterned SiO2 substrate to reproduce the measured transmission/reflection spectra. The results of the numerical simulation reveal the impact of the imperfectness of the gold layer on the performance of the THz metasurface. The experimental results are well described in terms of the Drude–Smith model of metal conductivity that takes into account the anisotropic scattering of the carriers in thin metal films.

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