Rare-earth-based single photon sources for quantum telecommunication

The project aims at the realization of single photon sources in the telecom wavelength regime, based on single rare-earth ions (like erbium or ytterbium) precisely doped into optical crystals by means of ion implantation (up to 200nm below the surface). The main advantage of the proposed single photon sources are their true single photon emission, their fourier-limited linewidth and the ability to store emitted photons directly in a medium based on rare-earth ions (straight forward interfacing). The typically low fluorescent signal of single erbium/ytterbium ions can be boosted by orders of magnitude through coupling them to optical resonators (fabricated from thin film lithium niobate) with high Q factors. The single photon source behaviour will be assessed by the indistinguishability of the emitted photons in a Hong-Ou-Mandel experiment.