Purcell-enhanced single-photon emission from nitrogen-vacancy centers coupled to a tunable microcavity

TL;DR

This paper demonstrates Purcell-enhanced single-photon emission from nitrogen-vacancy centers in nanodiamonds coupled to a tunable microcavity, achieving significant lifetime modification and promising applications in quantum technologies.

Contribution

It introduces a tunable fiber-based microcavity with ultra-small mode volume for enhanced emission from NV centers, and explores a new light confinement regime with high Purcell factors.

Findings

Achieved Purcell enhancement with a factor of up to 2.0.

Demonstrated tunable fluorescence lifetime modification.

Predicted Purcell factors up to 11 for NV centers in a novel confinement regime.

Abstract

Optical microcavities are a powerful tool to enhance spontaneous emission of individual quantum emitters. However, the broad emission spectra encountered in the solid state at room temperature limit the influence of a cavity, and call for ultra-small mode volume. We demonstrate Purcell-enhanced single photon emission from nitrogen-vacancy (NV) centers in nanodiamonds coupled to a tunable fiber-based microcavity with a mode volume down to $1.0\,\lambda^{3}$. We record cavity-enhanced fluorescence images and study several single emitters with one cavity. The Purcell effect is evidenced by enhanced fluorescence collection, as well as tunable fluorescence lifetime modification, and we infer an effective Purcell factor of up to 2.0. With numerical simulations, we furthermore show that a novel regime for light confinement can be achieved, where a Fabry-Perot mode is combined with additional mode confinement by the nanocrystal itself. In this regime, effective Purcell factors of up to 11 for NV centers and 63 for silicon vacancy centers are feasible, holding promise for bright single photon sources and efficient spin readout under ambient conditions.