Wavelength-Selective Polarization-Sensitive Near-Perfect Absorber Based on Metal-Dielectric-Graphene-Dielectric-Metal Stack

Absorption enhancement and tuning bear much importance in light harvesting and optoelectronic devices. In this study, we conducted a comprehensive study on the scopes and possibilities of enhancing absorption and ways to control it. We optimized a metal-dielectric-graphene-dielectric-metal (MDGDM) structure to harness maximum absorbance from the graphene layer at the desired wavelength regime. A graphene layer was designed to be placed in a sandwiched orientation between dielectric layers to absorb light. A ribbon grating comprised of Au slabs was employed on the top of the absorber to enhance the absorption at resonant wavelength. Our calculation suggests the possibility of > 150 nm absorption peak tuning and > 90% absorption via physical and nonphysical variation. Moreover, our proposed device demonstrated polarization-dependent absorption, revealing possibilities for designing polarization-selective broadband absorbers by utilizing multiple stacks of MDGDM.