Silicon Vacancy Defects in Diamond as Single Photon Source

For the applications in quantum information and experiments on the foundations of quantum mechanics a robust narrow-band single photon source is desirable. We report on single photon emission from the Silicon Vacancy (SiV) centers in diamond fabricated by ion implantation. Single SiV centers are photostable and have a spectrum consisting of a sharp zero phonon line (FWHM is about 5 nm) at 738 nm and only very weak vibronic sidebands at room temperature. The short luminescence lifetime of 1.2 ns enables an efficient generation of single photons. We employed nitrogen doping to suppress nonradiative transitions of single SiV centers and used a diamond solid immersion lens to improve the collection efficiency of single photons. It is promising to build an efficient single photon source based on the SiV centers.