Liquid Crystal Tunable Dielectric Metamaterial Absorber in the Terahertz Range

Abstract

In this paper, we propose a tunable dielectric metamaterial absorber in the terahertz (THz) range. The absorber is composed of a silicon pillar array embedded in a liquid crystal (LC) layer, which is sandwiched by two graphene electrodes. By way of varying the applied bias, the LC orientation can be continuously tuned. At a saturated bias, all LCs are vertically driven, and an absorption peak of 0.86 is achieved at 0.79 THz. When the bias is turned off, the same LCs are horizontally aligned, and the absorption peak degenerates into two smaller ones. A 47% modulation depth at 0.79 THz is obtained via numerical simulation with experimental feasibility considered. Such an active THz dielectric absorber may be utilized as part of various active THz apparatuses in THz imaging, sensing, switching, and filtering.