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arXiv · 1910.03149

Tunable Multifocal THz Metalens Based on Metal-Insulator Transition of VO2 Film

Roya Kargar·Kasra Rouhi·Ali Abdolali
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Abstract

Recently, metalenses which consist of metasurface arrays, have attracted attention due to their more condensed size in comparison with conventional lenses. In this paper, we propose a reconfigurable coding metasurface hybridized with vanadium dioxide (VO2) for wavefront manipulation at terahertz (THz) frequencies. At room temperature, the unit-cell can reflect as a "1" bit under linearly y polarized illuminated waves. Besides, when the temperature is increased, VO2 would be in a fully metallic state; therefore, unit-cell can act as a "0" reflection phase. Furthermore, by changing the unit-cells arrangements on a metalens surface, the proposed device can focus the incident beam at any position according to a particular design. Numerical simulations demonstrate that the designed VO2-assisted metasurface can generate one and multi-focal spot in reflection mode as expected. Also, theoretical results depict an excellent agreement with obtained simulation results. The presented metalens has notable potential in THz high-resolution imaging and optical coding.

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Roya Kargar, Kasra Rouhi, Ali Abdolali. 2019-10-08. Tunable Multifocal THz Metalens Based on Metal-Insulator Transition of VO2 Film. https://arxiv.org/abs/1910.03149

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