Terahertz Polarizers Based on 2D Ti<sub>3</sub>C<sub>2</sub>T<sub>z</sub> MXene: Spin Cast from Aqueous Suspensions
Guangjiang Li, Kiana Montazeri, Mostafa K. Ismail, Michel W. Barsoum, Bahram Nabet, Lyubov V. Titova
Abstract
Herein, the fabrication of terahertz (THz) polarizers is reported on by simply spin casting two‐dimensional (2D) MXene Ti 3 C 2 T z nanosheets on a photolithographically patterned THz‐transparent substrate and subsequent immersion in acetone. Lines 30 nm‐thick and 10–20 μm wide result in electric field (E) extinction ratios (ER) of up to 3 dB, or power ER of up to 6 dB. Simulations show the possibility of achieving ER beyond 16 dB, or power ER higher than 32 dB by increasing the thickness of the MXene lines to 1.5–2 μm and optimizing the metasurface patterns. The Ti 3 C 2 T z nanosheets are solution‐processed and can be deposited on a variety of substrates, including flexible ones. Once encapsulated, chemically stable THz polarizers, that combine high performance and low production costs, can be readily manufactured, with characteristics that compare favorably with the much more involved metallic wire grid polarizers, including gold and tungsten. Moreover, recent demonstration of dynamic tunability of Ti 3 C 2 T z THz conductivity by ultrafast optical pulses opens the possibility of using MXene wire‐grids in high‐speed THz modulators.