The NV centre coupled to an ultra-small mode volume cavity: a high efficiency source of indistinguishable photons at 200 K

TL;DR

This paper presents a silicon nitride cavity design that enables high-efficiency, near-indistinguishable photon emission from nitrogen vacancy centers in diamond at 200 K, advancing scalable quantum photonics.

Contribution

The authors design and simulate a compact silicon nitride cavity that achieves 99% photon extraction efficiency and over 50% photon indistinguishability at 200 K, suitable for scalable quantum technologies.

Findings

Achieves 99% photon extraction efficiency at 200 K.

Provides photon indistinguishability greater than 50%.

Design is compatible with standard silicon fabrication processes.

Abstract

Solid state atom-like systems have great promise for linear optic quantum computing and quantum communication but are burdened by phonon sidebands and broadening due to surface charges. Nevertheless, coupling to a small mode volume cavity would allow high rates of extraction from even highly dephased emitters. We consider the nitrogen vacancy centre in diamond, a system understood to have a poor quantum optics interface with highly distinguishable photons, and design a silicon nitride cavity that allows 99 % efficient extraction of photons at 200 K with an indistinguishability of > 50%, improvable by external filtering. We analyse our design using FDTD simulations, and treat optical emission using a cavity QED master equation valid at and beyond strong coupling and which includes both ZPL broadening and sideband emission. The simulated design is compact (< 10 um), and owing to its planar geometry, can be fabricated using standard silicon processes. Our work therefore points towards scalable fabrication of non-cryogenic atom-like efficient sources of indistinguishable photons.