Wavelength Tunable Microdisk Cavity Light Source with a Chemically Enhanced MoS₂ Emitter

Abstract

In this work, we report an integrated narrowband light source based on thin MoS2 emissive material coupled to the high quality factor whispering gallery modes of a microdisk cavity with a spatial notch that enables easy out-coupling of emission while it yields high spatial coherence and a Gaussian intensity distribution. The active light emitting material consists of chemically enhanced bilayer MoS2 flakes with a thin atomic layer deposited SiO2 protective coating that yields 20-times brighter chemically enhanced photoluminescence compared to as-exfoliated monolayers on the microdisk. Quality factors ≈ 1000 are observed as well as a high degree of spatial coherence. We also experimentally achieve effective index tuning of cavity coupled emission over a full free spectral range. The thermal response of this system is also studied. This work provides new insights for nanophotonic light sources with atomically thin active media.