Abstract: Single atoms and atom-like defects in solids are ideal quantum light sources and memories for quantum networks. However, most atomic transitions are in the ultraviolet-visible portion of the electromagnetic spectrum, where propagation losses in optical fibers are prohibitively large.
I will present recent results on the first observation of the emission of single photons from a single erbium (Er) ion in a solid-state host, whose optical transition at 1.5 microns in wavelength is in the telecom band, allowing for low-loss propagation in optical fiber. I will discuss how we enable this observation through the use of a hybrid device geometry involving silicon nanophotonic structures. These silicon photonic crystal cavities result in a Purcell enhancement of the photon emission rate by a factor of more than 650. Dozens of distinct ions can be addressed in a single device, and the splitting of the lines in a magnetic field confirms that the optical transitions are coupled to the electronic spin of the erbium ions. Finally, I will discuss future directions for this platform.