Mitigation of the small-scale self-focusing effect by a rotating laser beam in a high-power laser.

Intense lasers tend to produce nonlinear effects during propagating through the nonlinear media, which greatly limits the output power and beam quality of lasers. The approach against small-scale self-focusing (SSSF) of high-power lasers (HPLs) is proposed by using rotating beams generated by the coherent superposition of two vortex beams with opposite topological charges and frequency shift. The propagation model of rotating beams in the nonlinear medium is established, and the SSSF effects of the non-rotating and rotating beams are numerically simulated and comparatively analyzed. The results show that, compared with the non-rotating beam, the rotating beam can contribute to the reduction of the breakup integral and mid-high frequency components of the HPLs.