Electrically tunable dual-channel absorber based on a graphene integrated slanted grating cavity

Abstract

In this paper, we propose a tunable dual-channel absorber based on a monolayer of graphene combined with a slanted grating. A single-channel perfect absorption of a monolayer graphene structure at 850 nm was initially achieved in a Fabry-Perot cavity resonance. The absorption rate of graphene was enhanced by nearly 24.5 times. Furthermore, the symmetry of the grating is broken to excite the quasi-bound states in the continuum (quasi-BICs) resonance mode, resulting in another absorption channel at 878.8 nm, thus achieving a perfect dual-channel absorber. The absorption half-width and absorption wavelength can be adjusted by tuning the grating thickness and the electro-optical effect of the DAST material. Furthermore, adjusting the polarization angle of the incident light enables the transition between single- and dual-channel absorbers. The proposed device has potential applications in the fields of high-performance graphene-based optoelectronic devices and optical switching systems.