I know there are already some similar questions like Amplitude of an electromagnetic wave containing a single photon but I can't get my head around it since the answers there seem not to fit very precisely to the question: What is the amplitude of a single photon? I know the energy of a photons depends strictly on its frequency and light is described by electromagnetic waves. Are (single) photons also seen as electromagnetic waves? If so, what does it amplitude then tell? Thank you!