If an electron is in an excited state it can return to a lower energy ... will produce a photon of a different frequency and hence a different colour. This causes line emission spectra to be ...

Radiation within the visible spectrum can appear black if it is low in power – more specifically, lower in power than its ...

Taking these together with the pixel information, it is possible to calculate the average photon arrival time per pixel and to generate an image that contains both the intensity (photon counts ...