Optical repumping of resonantly excited quantum emitters in hexagonal boron nitride

TL;DR

This paper introduces an optical repumping method using a weak non-resonant laser to stabilize and enhance the resonance fluorescence of quantum emitters in hexagonal boron nitride, advancing quantum photonics applications.

Contribution

It demonstrates a two-laser repumping scheme that significantly improves the stability and brightness of quantum emitters in hBN, enabling more reliable quantum photonic devices.

Findings

Resonant excitation alone causes emitter decay to dark states.

A weak non-resonant laser reduces dark state transitions.

Overall ON time of emitters increased by an order of magnitude.

Abstract

Resonant excitation of solid-state quantum emitters enables coherent control of quantum states and generation of coherent single photons, which are required for scalable quantum photonics applications. However, these systems can often decay to one or more intermediate dark states or spectrally jump, resulting in the lack of photons on resonance. Here, we present an optical co-excitation scheme which uses a weak non-resonant laser to reduce transitions to a dark state and amplify the photoluminescence from quantum emitters in hexagonal boron nitride (hBN). Utilizing a two-laser repumping scheme, we achieve optically stable resonance fluorescence of hBN emitters and an overall increase of ON time by an order of magnitude compared to only resonant excitation. Our results are important for the deployment of atom-like defects in hBN as reliable building blocks for quantum photonic applications.