▎ 摘　　要

A graphene-based tunable absorber consisting of a graphene monolayer on a dielectric grating and dielectric gap layer backed with a substrate is proposed and investigated. The absorber exhibits higher than 80% absorption at resonance, which is attributed to the guided mode resonances (GMRs) of a simple one-dimensional dielectric grating. Furthermore, the ultra-narrow spectrum and antenna-like response make it able to be used as a thermal emitter with high directionality. The physical mechanism of such perfect absorption performance is disclosed by the illustrated electric field distributions. Lastly, the influence of Fermi level and relaxation time on the absorption spectra is investigated, which will benefit the design of graphene-based devices. The results indicate that it will promote the development of graphene-based tunable devices when combining graphene with general GMRs effect. (C) 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)