Implementing the Dual Functions of Switchable Broadband Absorption and Sensitive Sensing in a VO2-Based Metasurface

The metadevice with multiple functions in a fixed nanostructure is highly required. In this paper, we numerically achieved the dual functions of switchable broadband absorption and sensitive refractive index (RI) sensing in a fixed fishnet-shaped nanostructure by integrating with the phase change material vanadium dioxide (VO2). Exploiting the insulator-to-metal transition of VO2, the absorption strength could be dynamically switched from 0.07 to 0.97 in a broad terahertz (THz) band. Meanwhile, the same structure with metallic VO2 exhibits highly sensitive RI sensing performance. The sensitivity reaches 1.15 THz/RIU, which makes great progress. The proposed metasurface with dual functions will promote the development and applications of THz nanodevices.