Design of narrowband perfect absorber for enhancing photoluminescence in atomically thin WSe2

Abstract Based on the Fabry–Perot (FP) resonance and guide resonance, the perfect absorber with the cross-bar nanostructure is designed for enhancing photoluminescence in atomically thin WSe2. The absorption of monolayer WSe2 could reach 89.4% with an Ag mirror structure and an amazing 99.9% at the resonance wavelength in an all-dielectric system. In addition, the perfect absorber is insensitive to the incident angle of the light, which is valuable to the photoluminescence system and device that need incident angular tolerance. The design shows new possibilities for enhancing light-matter interaction in 2D materials and would benefit the design of high-efficiency 2D materials based photoluminescence and photodetection devices.