Enhanced Emission from WSe2 Monolayers Coupled to Circular Bragg Gratings

TL;DR

This paper demonstrates enhanced and directional emission from WSe2 monolayers coupled to circular Bragg gratings, achieving high spin valley contrast, advancing on-chip nanophotonics integration.

Contribution

It introduces a novel hybrid structure coupling WSe2 monolayers with circular Bragg gratings, enhancing emission and polarization contrast for nanophotonic applications.

Findings

Achieved Purcell-enhanced emission from WSe2 monolayers

Improved emission directionality using symmetric grating structures

Recorded high spin valley contrast (>40%) in polarization measurements

Abstract

Two-dimensional transition-metal dichalcogenides (TMDC) are of great interest for on-chip nanophotonics due to their unique optoelectronic properties. Here, we propose and realize coupling of tungsten diselenide (WSe2) monolayers to circular Bragg grating structures to achieve enhanced emission. The interaction between WSe2 and the resonant mode of the structure results in Purcell-enhanced emission, while the symmetric geometrical structure improves the directionality of the out-coupling stream of emitted photons. Furthermore, this hybrid structure produces a record high contrast of the spin valley readout (> 40%) revealed by the polarization resolved photoluminescence (PL) measurements. Our results are promising for on-chip integration of TMDC monolayers with optical resonators for nanophotonic circuits.