Highly Enhanced Directional Emission from Emitter-Integrated Dielectric Metasurfaces: Role of the Emitter Layer

Abstract

Combining semiconductor quantum dots (QDs) with dielectric metasurfaces offers a promising platform for enhancing and controlling light emission properties. Highly enhanced directional and polarized emission is experimentally demonstrated from dielectric metasurfaces integrated with colloidal QDs. Specifically, emission enhancements from InP/ZnS QD- and CdSe/ZnS QD-integrated metasurfaces are directly compared. It is found that low absorption losses in the emitter layer can drastically increase the maximum achievable enhancement when different QDs are coated on the same metasurface. In particular, the lower intrinsic losses of the InP/ZnS QD layer enable dramatically enhanced vertical emission with narrow angular divergence, achieving a 140-fold enhancement in experiment. Our detailed experimental and theoretical investigations indicate the critical role of the emitter layer in the design of the emitter-integrated metasurface. Strong agreement between simulation and experiment confirms the critical-coupling behavior in maximized emission enhancement. Our study provides general guidelines for the development of directional light sources. Compact light sources with high directionality and controlled polarization hold strong potential for applications in displays, optical communications, sensing, and imaging.