Investigations of Nonlinear Polarization Transfer Between Obliquely Intersecting Beams

Electromagnetic waves propagating through a plasma can interact nonlinearly through a variety of different mechanisms. The excitation of a plasma beat wave (ions or electrons) can create a refractive index modulation that changes the dispersion of the interacting beams. Alternatively, high-intensity beams can enter the regime where relativistic nonlinearities influence the propagation dynamics. In recent studies [Kur E., et al. "Nonlinear polarization transfer and control of two laser beams overlapping in a uniform nonlinear medium", Opt. Express 29, 1162-1174 (2021)], it was proposed that two beams propagating along the same axis can exchange their polarization state due to nonlinear interaction. Here we present a numerical analysis of two laser beams intersecting in a nonlinear medium at varying angles. Polarisation transfer is observed as predicted by analytical theory for a range of angles. For small angles, it is found that filamentation of the interacting beams becomes important. Analytical estimates of the filamentation threshold are presented and good agreement is found with the simulation data.