Nanodiamonds with photostable, sub-gigahertz linewidths quantum emitters

Single photon emitters with narrow linewidths are highly sought after for applications in quantum information processing and quantum communications. In this letter, we report on a bright, highly polarized near infrared single photon emitter embedded in diamond nanocrystals with a narrow, sub GHz optical linewidths at 10K. The observed zero phonon line at ~ 780 nm is optically stable under low power resonant excitation and blue shifts as the excitation power increases. Our results highlight the prospect for using new near infrared color centers in nanodiamonds for quantum applications.