Optical branched flow in nonlocal nonlinear medium.

When light propagates through a randomly correlated, slowly varying medium, it generates optical branched flow. Previous studies have demonstrated that the self-focusing effect in optical media can accelerate the appearance of the first branching points and sharpen the filaments of branched flow. In this study, we investigate the influence of the nonlocality of the nonlinear response on branched flow. We find that, due to its averaging effect, as the range of nonlocality increases, the first branching point shifts to a greater distance, and the flow structures broaden, thus nonlocality ultimately restores the branched flow to its linear condition. We have developed a semi-analytical formula and confirmed the screening of the self-focusing effect on branching flow by nonlocality.