Multifunctional VO₂-Liquid Crystal Hybrid Metamaterials for Dual-Controlled Terahertz Absorption

Tunable terahertz (THz) metamaterial devices, especially for absorbers, have been widely investigated in recent decades. However, the conventional absorbers are limited in functionality, with the fixed absorption rate in various applications. Here, we propose a multifunctional, tunable THz absorber based on a VO₂-liquid crystal hybrid metamaterial, which allows for the independent control of absorption rate and operating frequency. Based on the insulator-metal phase transition of VO₂, the device achieves an adjustable absorption range from 1.24% to 99.95% through external thermal excitation. At high temperatures, VO₂ transforms into a metallic state, and the device demonstrates two narrow-linewidth THz absorption peaks with the efficiencies close to 100%. Additionally, the continuous control of the absorption frequencies can be achieved by using an externally applied electric field to change the orientations of the liquid crystal molecules. The simulated surface electric fields further elucidate the physical mechanisms driving the adjustable characteristics of the absorber. This hybrid VO₂ and liquid crystal THz metamaterial absorber shows strong potential for enhancing THz applications in imaging, modulation, and high-speed communication.