  Defect-based quantum emitters in solid state materials offer a promising
platform for quantum communication and sensing. Confocal fluorescence
microscopy techniques have revealed quantum emitters in a multitude of host
materials. In some materials, however, optical properties vary widely between
emitters, even within the same sample. In these cases, traditional ensemble
fluorescence measurements are confounded by heterogeneity, whereas individual
defect-by-defect studies are impractical. Here, we develop a method to
quantitatively and systematically analyze the properties of heterogeneous
emitter ensembles using large-area photoluminescence maps. We apply this method
to study the effects of sample treatments on emitters in hexagonal boron
nitride, and we find that low-energy (3 keV) electron irradiation creates
emitters, whereas high-temperature (850 $^\circ$C) annealing in an inert gas
environment brightens emitters.
