Monolithic Integration of Single Quantum Emitters in hBN Bullseye Cavities

TL;DR

This paper demonstrates a monolithic circular Bragg grating device in hexagonal boron nitride that enhances single-photon collection efficiency and spectral stability, advancing integrated quantum photonics.

Contribution

It introduces a fabrication process for monolithically integrating quantum emitters with circular Bragg gratings in hBN, improving photon collection and stability.

Findings

6-fold increase in photon collection efficiency

Exceptional spectral stability at cryogenic temperatures

Successful fabrication using diverse etching methods

Abstract

The ability of hexagonal boron nitride to host quantum emitters in the form of deep-level color centers makes it an important material for quantum photonic applications. This work utilizes a monolithic circular Bragg grating device to enhance the collection of single photons with 436 nm wavelength emitted from quantum emitters in hexagonal boron nitride. We observe a 6- fold increase in collected intensity for a single photon emitter coupled to a device compared to an uncoupled emitter, and show exceptional spectral stability at cryogenic temperature. The devices were fabricated using a number of etching methods, beyond standard fluorine-based reactive ion etching, and the quantum emitters were created using a site-specific electron beam irradiation technique. Our work demonstrates the potential of monolithically-integrated systems for deterministically-placed quantum emitters using a variety of fabrication options.