by Nanyang Technological University Comparing classical and quantum theories for Smith-Purcell radiation. In classical theory, the emitted photon spectrum (a) and the post-selected electron energy loss spectrum (EELS) (b) are regularly spaced at integer multiples of the fundamental frequency ω0, i.e., 0, 2ω0, 4ω0, 6ω0, etc. Post-selection here refers to recording of electron energy loss signals...
