Purcell enhancement in layered InSe on the Mie-resonant silicon nitride waveguide

Abstract

Hybrid integration of layered van der Waals (vdW) semiconductors with dielectric resonant structures provides an effective approach for controlling excitonic emission dynamics. Here, we demonstrate Purcell-enhanced spontaneous emission from a thin InSe flake integrated with a Mie-resonant Si$_3$N$_4$ waveguide. The structure is designed to spectrally overlap with the InSe photoluminescence band and enhance coupling of excitonic emission to the guided mode. Time-resolved photoluminescence shows a reduction of the excitonic decay time by up to a factor of three relative to planar InSe. The extracted Purcell factors are approximately 3 for out-of-plane excitons and 2.1 for in-plane excitons. These results demonstrate resonator-induced control of excitonic recombination in layered InSe and highlight vdW-dielectric interfaces as a platform for integrated excitonic and quantum photonic devices.