Broadband and bi-functional switchable terahertz metadevices based on VO2-assisted coding metasurfaces

Active metasurfaces (AMSS), featuring integrated active elements, offer a highly precise means of achieving tunable and reconfigurable functionalities that haves the potential to revolutionize the dynamic manipulation of electromagnetic waves. Here, we propose a broadband and bi-functional switchable metadevice operating in the same frequency band by combining a metasurface with VO
2
. The metasurface acts as polarization converter/absorber for the insulating/metallic phase of VO
2
with a switchable characteristic. To better highlight the device’s switchability, we further design 1-bit/2-bit metasurfaces to realize dynamic switching between beam splitting/focusing and absorbing. The active metadevices can be widely utilized in terahertz communications, sensing and spectroscopy.