Spin dynamics of single erbium ions

Single Er$^{\mathrm{3+\thinspace }}$ions in solid-state hosts are promising single photon sources and quantum memories for quantum repeaters, because of their optical transition at 1.5 $\mu $m in the telecom C-band where fiber transmission losses are minimized. The central challenge of this approach is the low natural photon emission rate resulting from the dipole-forbidden nature of the 1.5 $\mu $m transition. We have demonstrated that this can be overcome by integrating the ions in a low loss, small mode-volume silicon nanophotonic cavity and Purcell enhancing the emission rate by over a factor of 650 [1], enabling the optical observation of single Er$^{\mathrm{3+}}$ ions for the first time. We will also discuss ongoing work to probe the dynamics of the Er$^{\mathrm{3+}}$ ions' spins and generate spin-photon entanglement, as well as studies of the interactions between nearby Er$^{\mathrm{3+}}$ ions in dense clusters. These results will pave the way towards developing scalable, long-distance quantum networks based on silicon nanophotonics and Er$^{\mathrm{3+}}$ ions. \newline [1] A. M. Dibos, M. Raha, C. M. Phenicie, J. D. Thompson, Phys. Rev. Lett. 120, 243601 (2018)