Multifunctional phase modulated metasurface based on a thermally tunable InSb-based terahertz meta-atom

Abstract

Terahertz (THz) metasurfaces composed of Pancharatnam-Berry (PB) meta-atoms have great potential for applications in THz imaging, biological sensing, and optical communication. However, traditional THz PB metasurfaces suffer from inflexible electromagnetic responses and complicated structures. Here, we propose a thermally tunable reflection-type InSb-based THz PB meta-atom, which can not only convert the incident circularly-polarized (CP) wave into cross-polarized components but also adjust the reflection efficiency by increasing the temperature of InSb from 220 K to 360 K. Moreover, various functional devices, including anomalous reflector, reflection-type metalens, and reflection-type OAM beam generators, are investigated with the finite difference time-domain (FDTD) method by using the proposed meta-atom. The working states of these devices can be switched from “ON” to “OFF” at the frequency of 1 THz successfully by changing the temperature of InSb from 220 K to 360 K. This work not only paves a way for the study of tunable multifunctional THz PB devices, but also promotes the practical applications of THz metasurfaces.