Another approach is using the g(2) function. The g(2) function, well-known from quantum optics, provides a very useful tool in this context. g(2) imaging can be used to identify and characterize single-photon emitters at the nanoscale. As such, it can be employed in the context of fundamental studies on quantum systems and their interaction with electron beams. Furthermore, it can be used to study bunching in extended systems with multiple emission centers which can be connected to the emission lifetime and excitation efficiency. One of the main benefits of this approach is that it can be performed with a continuous electron beam so no adaptations to the electron microscope are required. This approach is valuable for studies on dielectrics and semiconductor systems to name a few.