Dual-band spin-dependent perfect absorber with anisotropic thin films in mid-infrared range

Abstract Motivated by the imperative demand for chirality manipulation within mid-infrared (mid-IR) range, this study presents an innovative solution to obtain selective perfect absorption and chiroptical responses with conventional Otto configuration. Optical responses of the structure have been calculated numerically by the 4×4 anisotropic transfer matrix method (ATMM). The results show that the proposal supports the chiral response with dual-band resonance in absorption spectra by displaying different properties for left-hand circular polarization (LCP) and right-hand circular polarization (RCP) light, its circular dichroism (CD) and working wavelength could be tuned by adjusting the layer thickness and incidence angle. It is demonstrated that the proposed device exhibits an extraordinary absorption efficiency of unity for RCP light and zero for LCP light at a wavelength of 9.32 μm, accompanied by a maximum CD in absorption of -1. The strategy in manipulating dual-band selective chiroptical (CO) responses holds great potential in realizing mid-IR devices capable of chirality manipulation.