Broadband switchable terahertz half-/quarter-wave plate based on VO2-metal hybrid metasurface with over/underdamped transition

TL;DR

This paper introduces a broadband, dynamically switchable terahertz wave plate using a VO2-metal hybrid metasurface, enabling polarization control over a broad frequency range by exploiting phase transition properties.

Contribution

A novel design approach for broadband, switchable terahertz wave plates using VO2-metal hybrid metasurfaces based on resonance transition mechanisms.

Findings

Switchable between HWP and QWP with >96% polarization conversion

Operates over a broad 0.8-1.2 THz frequency band

Achieves high efficiency through VO2 phase transition

Abstract

Dynamically switchable half-/quarter-wave plates have recently been the focus in the terahertz regime. Conventional design philosophy leads to multilayer metamaterials or narrowband metasurfaces. Here we propose a novel design philosophy and a VO2-metal hybrid metasurface for achieving broadband dynamically switchable half-/quarter-wave plate (HWP/QWP) based on the transition from the overdamped to the underdamped resonance. Results show that, by varying the VO2 conductivity by three orders of magnitude, the proposed metasurface's function can be switched between an HWP with polarization conversion ratio larger than 96% and a QWP with ellipticity close to -1 over the broad working band of 0.8-1.2 THz. We expect that the proposed design philosophy will advance the engineering of metasurfaces for dynamically switchable functionalities beyond the terahertz regime.