Efficient fiber in-line single photon source based on colloidal single quantum dots on an optical nanofiber

We demonstrate a fiber in-line single photon source based on a hybrid system of colloidal single quantum dots deposited on an optical nanofiber and cooled down to cryogenic temperature (3.7 K). We show that a charged state (trion) of the single quantum dot exhibits a photo-stable emission of single photons with high quantum efficiency, narrow linewidth (3 meV FWHM) and fast decay time (10.0 ± 0.5 ns). The single photons are efficiently coupled to the guided modes of the nanofiber and eventually to a single mode optical fiber. The brightness (efficiency) of the single photon source is estimated to be 16 ± 2 % with a maximum photon count rate of 1.6±0.2 MHz and a high single photon purity (g²(0) = 0.11 ± 0.02). The device can be easily integrated to the fiber networks paving the way for potential applications in quantum networks.