In this video the process of fluorescence is explained as well as what fluorescence anisotropy actually is. Then a calculation to determine binding affinity is shown. Link to reference textbook: www.amazon.com/Principles-Flu...
Good point. Fluorescence is certainly not the only type of photon emission! In the natural world, as far as I understand, multiple types of photon emission happen as well as other ways of orbital thermodynamics.