Abstract

The ultrawide tunable terahertz (THz) phase shifter has always been in high demand by THz applications, especially in terms of broadband transmission and phase modulation. In this paper, we design and fabricate a composite device that combines a double-layer liquid crystal (LC) with a double-sided etched grating metasurface. By introducing the natural anisotropy of LC based on the artificial anisotropy of the metasurface, the anisotropy of the device is significantly enhanced, and this anisotropy can be dynamically modulated by an external field. When the LC molecules rotate in the $x \!-\! y$ plane, the experimental results show that the phase difference can vary between ${-}{{83}}^\circ$ and 277° at 0.52 THz with a large phase-shift modulation depth of 360° (i.e., ${{2}}\pi$). The same phase-shift modulation depth can be obtained when the LC molecules rotate in the $x \!-\! z$ plane, in which the phase difference can vary between 207° and 567° at 1.14 THz. Our proposed composite device shows an ultrawide phase shift regulation and an ultra-large phase-shift modulation depth in the THz regime, which may provide a new strategy for various THz phase and polarization devices.

© 2023 Optica Publishing Group

Dynamic terahertz anisotropy and chirality enhancement in liquid-crystal anisotropic dielectric metasurfaces

Hui-Jun Zhao, Fei Fan, Tian-Rui Zhang, Yun-Yun Ji, and Sheng-Jiang Chang
Photon. Res. 10(4) 1097-1106 (2022)

Tunable terahertz phase shifter based on dielectric artificial birefringence grating filled with polymer dispersed liquid crystal

Xin Zhang, Fei Fan, Chun-Yue Zhang, Yun-Yun Ji, Xiang-Hui Wang, and Sheng-Jiang Chang
Opt. Mater. Express 10(2) 282-292 (2020)

Active terahertz beam deflection based on a phase gradient metasurface with liquid crystal-enhanced cavity mode conversion

Yunyun Ji, Xinhao Jiang, Fei Fan, Huijun Zhao, Jierong Cheng, Xianghui Wang, and Shengjiang Chang
Opt. Express 31(2) 1269-1281 (2023)

Electrically tunable dual-layer twisted nematic liquid crystal THz phase shifters with intermediate composite polymer thin film

Anup Kumar Sahoo, Yi-Hsin Lin, Chan-Shan Yang, Osamu Wada, Chun-Ling Yen, and Ci-Ling Pan
Opt. Mater. Express 12(12) 4733-4754 (2022)

Terahertz artificial birefringence and tunable phase shifter based on dielectric metasurface with compound lattice

Yun-Yun Ji, Fei Fan, Meng Chen, Lei Yang, and Sheng-Jiang Chang
Opt. Express 25(10) 11405-11413 (2017)