Coherence properties of photons emitted by single defect centers in diamond

TL;DR

This paper investigates the coherence properties of photons emitted by nitrogen-vacancy centers in diamond, demonstrating near-lifetime-limited photon emission and high interference contrast, which are promising for quantum network applications.

Contribution

It provides experimental measurements of photon coherence times and interference contrast from NV centers, highlighting their suitability for quantum information processing.

Findings

Photon emission is close to Fourier transform limited.

High two-photon interference contrast (0.8) achieved.

Excited state lifetimes of 12 and 7.8 ns depending on spin state.

Abstract

Photon interference among distant quantum emitters is a promising method to generate large scale quantum networks. Interference is best achieved when photons show long coherence times. For the nitrogen-vacancy defect center in diamond we measure the coherence times of photons via optically induced Rabi oscillations. Experiments reveal a close to Fourier transform (i.e. lifetime) limited width of photons emitted even when averaged over minutes. The projected contrast of two-photon interference (0.8) is high enough to envisage the applications in quantum information processing. We report 12 and 7.8 ns excited state lifetime depending on the spin state of the defect.