Dual functional metasurface with broadband polarization conversion and perfect absorption

Abstract

A dual-functional metasurface based on vanadium dioxide (VO2) and operating in the infrared region is proposed in this paper. The photonic metasurface consists of a double-split ring resonator and the gaps are loaded with VO2 to achieve dual-functionality. The proposed metasurface functions as a polarization converter at a temperature (T) of 358 K when VO2 is in insulating state. In this state, broadband linear to cross polarization is achieved with an excellent polarization conversion ratio (PCR) of > 98% in the 2702–4687 nm wavelength range. At a lower temperature (303 K), VO2 is in the metallic state and the metasurface functions as a wideband absorber with an absorptivity of > 90% in the wavelength range from 3896 − 4615 nm. There is a significant overlap in the frequency responses of the absorber and polarization converter leading to dual-functional behavior of the metasurface. Therefore, the structure is thermally tunable and suitable for optical and photonic applications.