Sapphire fiber metalens for THz photoconductive devices
N.V. Zenchenko (1), I.A. Glinskiy (1), D.V. Lavrukhin (1), G.M. Katyba (2,3),
E.V. Yakovlev (4), K.I. Zaytsev (2,4), and D.S. Ponomarev (1,2)
1– Institute of Ultra High Frequency Semiconductor Electronics of RAS, Moscow 117105, Russia
2 – Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow 119991, Russia
3 – Institute of Solid State Physics of the Russian Academy of Sciences, Chernogolovka 142432, Russia
4 – Bauman Moscow State Technical University, Moscow 105005, Russia
Abstract
We report on a sapphire fiber metalens that could be used to enhance the radiated THz power of photoconductive device when the metalens is mounted on its surface. We demonstrate that the metalens provides a spatial distribution of the photocarriers in the photoconductive gap depending on its diameter leading to efficient confinement of the photocarriers in the vicinity of the antenna electrodes when optimized.
Thanks to the dielectric nature of the metalens and high dielectric constant of the sapphire in optical and THz spectrum range [3], we numerically estimate the field enhancement factor of ~10 for the 220 µm thick diameter metalens at an excitation wavelength of 800 nm. Then we developed the experimental setup utilizing a high-resolution optical microscope and a micropositioner to provide accurate and precise mechanical placement of the metalens onto the surface of the photoconductive device.
Speaker
N.V. Zenchenko
Institute of Ultra High Frequency Semiconductor Electronics of RAS
Russian Feredation
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