Investigation of a broadband and polarization-insensitive optical absorber based on closed-ring resonator

Abstract

A broadband and polarization-insensitive optical metamaterial absorber (MA) based on the refractory metal chromium (Cr) closed-ring resonator is theoretically investigated. The semiconducting silicon dioxide (SiO[Formula: see text] thin film is introduced as the space layer in this sandwiched structure. Utilizing the symmetrical geometry of the proposed MA structure, polarization insensitivity of the broadband absorption is gained. The simulation results show that the absorber with Cr closed-ring array obtains an average absorption of 99.25% from 400[Formula: see text]nm to 900[Formula: see text]nm, covering the total visible wavelength range. This compact design may have potential applications in solar energy harvesting, thermal imaging, and emissivity control.