  Recent efforts to define microscopic solid-immersion-lenses (SIL) by focused
ion beam milling into diamond substrates that are registered to a preselected
single photon emitter are summarized. We show how we determine the position of
a single emitter with at least 100 nm lateral and 500 nm axial accuracy, and
how the milling procedure is optimized. The characteristics of a single
emitter, a Nitrogen Vacancy (NV) center in diamond, are measured before and
after producing the SIL and compared with each other. A count rate of 1.0
million counts per second is achieved with a $[111]$ oriented NV center.
