Relative phase interactions of two copropagating laser beams in underdense plasmas at different intensities and spot sizes

Abstract

The mutual interactions of two copropagating laser beams at a relative phase are studied using a two-dimensional fluid code. The interactions are investigated in underdense plasma at selected beam configurations and beam parameters for two separate nonlinearities, i.e., the ponderomotive and the relativistic nonlinearity. The selected beam configurations are introduced by different initial transverse spot size perturbations ͑finite and infinite͒ and different initial transversal intensity distributions ͑nonuniform and uniform͒ over those spot sizes and the selected beam parameters are given by different initial beam intensities relevant to each nonlinearity. In the ponderomotive nonlinearity, simulation results show that no mutual interactions are demonstrated between the copropagating beams regardless of the initial beam configurations and parameters. In nonlinear relativistic simulations, the mutual interactions between the beams are clearly observed, a mutual repulsion is formed in the presence of initial intensities that are nonuniformly distributed over finite spot sizes, and an effective strongly modulated mutual attraction takes places in the presence of initial intensities that are uniformly distributed over infinite spot sizes. Moreover, it is found in these simulations that increasing the initial beam intensities improves the attraction properties between the copropagationg beams.

Effect of polarization entanglement in photon-photon scattering

“…However, although our results are unlikely to have any experimental implications for photon-photon scattering in vacuum in the near future, their implications in photon-photon scattering in non-linear optical media [27], cavities [28], gases [29], plasmas [30][31][32][33] and with Rydberg atoms [34,35] could be observable.…”

Energy shift between two relativistic laser pulses copropagating in plasmas

“…In the relativistic regime, similar interaction properties * Electronic address: zcangtao@iapcm.ac.cn † Electronic address: taiwu.huang@szu.edu.cn have also been found in plasmas [26][27][28][29][30][31][32]. Plasma can be regarded as a kind of nonlinear medium that is already breakdown and in principle can tolerate ultra-strong laser fields.…”

“…Ren et al observed the spiraling interaction of two laser beams with crossed polarization directions [27,28]. Mahdy studied the interaction process of two laser beams that are out of phase at different intensities and spot sizes [29]. However, so far, the effects of the relative phase difference (φ) between the two coherent laser beams are not explored yet.…”

Ultrashort filaments dynamics of two laser beams propagation in underdense plasmas

“…In this regard, we simulated the propagation of a fs beam with an initial input energy E 01 = 2.4µJ in air plasma (n e = 10 15 cm −3 ). We conducted this simulation by numerically solving [16] a 2D envelope equation [17] in the Quasi Statics Approximation (QSA) coordinate [18], the result of this simulation is shown in figure 1. As displayed in this figure, a structure of a periodically self-focused and de-focused beam is clearly demonstrated at propagation time t = 120ps, the demonstrated structure is the ultrashort filament formation in underdesnse plasma.…”