Efficient extraction of zero-phonon-line photons from single nitrogen-vacancy centers in an integrated GaP-on-diamond platform

TL;DR

This paper presents GaP-on-diamond disk resonators that significantly enhance the collection efficiency of zero-phonon-line photons from single NV centers, advancing scalable quantum network development.

Contribution

Introduction of GaP-on-diamond resonators that resonantly couple NV center ZPL photons to waveguides, achieving up to 9% emission into the guided mode and demonstrating Purcell enhancement.

Findings

Achieved 9% probability of ZPL photon emission into waveguide mode.

Verified single-photon emission and Purcell enhancement.

Demonstrated potential for scalable quantum networks.

Abstract

Scaling beyond two-node quantum networks using nitrogen vacancy (NV) centers in diamond is limited by the low probability of collecting zero phonon line (ZPL) photons from single centers. Here, we demonstrate GaP-on-diamond disk resonators which resonantly couple ZPL photons from single NV centers to single-mode waveguides. In these devices, the probability of a single NV center emitting a ZPL photon into the guided waveguide mode after optical excitation can reach 9%, due to a combination of resonant enhancement of the ZPL emission and efficient coupling between the resonator and waveguide. We verify the single-photon nature of the emission and experimentally demonstrate both high in-waveguide photon numbers and substantial Purcell enhancement for a set of devices. These devices may enable scalable integrated quantum networks based on NV centers.