Angularly dense comb-like enhanced absorption of graphene monolayer with attenuated-total-reflection configuration

A multiline absorber based on the excitation of guided-mode resonance of one-dimensional photonic crystals (1D-PhCs), including a surface graphene monolayer under the attenuated-total-reflection configuration, is proposed and demonstrated. By carefully designing the structure parameters of the 1D-PhCs, the guided mode can be modulated by the periodic distribution of the refractive index. Our results reveal that the critical coupling of the guided resonance in periodical PhCs to graphene produces the perfect absorption. The number of absorption peaks within the photonic band corresponds to the number of unit cells. An ultrahigh Q-factor value of 4.75×10⁶ is obtained at resonance with unity absorption, which could serve as a promising replacement of metallic thin film as a sensor probe for future biosensing applications.