Generation of circularly polarized harmonic radiation by two color laser beams propagating in plasma

Abstract

An analytical study of the generation of even and odd harmonics by the propagation of two color circularly polarized laser beams through homogeneous, underdense plasma has been presented. The two laser beams are considered to be either co-rotating (co-polarized) or counter-rotating (counter-polarized). Considering the mildly relativistic regime of laser plasma interaction, a perturbative technique is used to evaluate the amplitude of various harmonic frequencies. It is shown that the even and odd harmonics of the fundamental laser frequency arise due to counter- as well as co-polarized laser fields. The generated harmonics are seen to be circularly polarized.