title: Integrated and compact fiber-coupled single-photon system based on nitrogen-vacancy centers and gradient-index lenses.
abstract: A fiber-coupled single-photon system is presented. Gradient-index lenses are utilized for single-photon collection and fiber coupling of a nitrogen-vacancy defect center in a nanodiamond. Integrated filter technology separates excitation and laser light. Therefore, the system is ultracompact with 120 mm(3) in dimension as no bulky free beam optics are used. The commercial availability of all components and their simple assembly allows the implementation of a low-cost single-photon system, possibly approaching single-photon count rates of 500 kcts/s.
authors: Institute of Physics, Nano-Optics, Humboldt-Universität zu Berlin, 12489 Berlin, Germany. tim.schroeder@physik.hu‑berlin.de
authors: Tim
authors: T
authors: Schröder
authors: Philip
authors: P
authors: Engel
authors: Eberhard
authors: E
authors: Schmidt
authors: Oliver
authors: O
authors: Benson