Nonlinear Scattering of Partially Coherent Radiation by Free Electrons

Abstract

Cross section for second harmonic generation in Compton scattering is obtained, both quantum-mechanically and classically, for radiation field of general nature in terms of fourth order coherence functions. Strong dependence of this cross-section on the nature of incident radiation is shown by studying the special cases of coherent and chaotic beams of radiation having various polarizations, and some cases of beams of radiation having stabilized amplitude. It is shown that the results reported in literature for this phenomenon hold only for coherent radiation and that those reported for unpolarized radiation are not correct. It is also shown that fourth order coherence functions can be determined from the measurements of the intensity of second harmonic scattered radiation in different directions and the coherent states of radiation can be distinguished from the generalized coherent states.