Nonlinear Compton scattering of polarized photons in plane-wave backgrounds

Abstract

We investigate the phenomenology of nonlinear Compton scattering of polarized photons by unpolarized electrons in plane-wave backgrounds. The energy and angular spectra of polarized photons are calculated for linearly and circularly polarized pulses, monochromatic fields and constant crossed field backgrounds. When the field intensity is in the weakly nonlinear regime, photons in different polarization states are predicted to possess very different energies and angular distributions. We explain this difference by calculating the spectrum for nonlinear Thomson scattering in a linearly polarized monochromatic background and projecting the electron's trajectory onto the different polarization directions. Finally, we calculate a scenario for multi-GeV electrons and, by considering the energy and angular-resolved photon polarization purity, find one can achieve a GeV-photon beam with polarization purities of over $90%$.