We report on the coherence properties of single photons from chromium-based colour centres in diamond. We use field-correlation and spectral lineshape measurements to reveal the interplay between slow spectral wandering and fast dephasing mechanisms as a function of temperature. We show that the zero-phonon transition frequency and its linewidth follow a power-law dependence on temperature indicating that the dominant fast dephasing mechanisms for these centres are direct electron-phonon coupling and phonon-modulated Coulomb coupling to nearby impurities. Further, the observed reduction in the quantum yield for photon emission as a function of temperature is consistent with the opening of additional nonradiative channels through thermal activation to higher energy states predominantly and indicates a near-unity quantum efficiency at 4 K.
@article{arxiv.1208.5628,
title = {Phonon-induced dephasing of chromium colour centres in diamond},
author = {Tina Muller and Igor Aharonovich and Zhe Wang and Xin Yuan and Stefania Castelletto and Steven Prawer and Mete Atature},
journal= {arXiv preprint arXiv:1208.5628},
year = {2015}
}