Spatial Modulation Suppression Concept for Multi‐Pump Interference Effect Mitigation in Stimulated Brillouin Amplification Beam Combining

ABSTRACT High pulse energy, high average power lasers with low spatial modulation have attracted many advanced applications in scientific research, and beam combination through stimulated Brillouin amplification (SBA) offers the potential for energy scaling with repetitive operation. However, attaining low‐modulation beam combining output remains a significant challenge due to the near‐field interference induced by the overlapping configuration of multiple pump beams with identical frequencies during the SBA process. Here, the method for reducing spatial modulation intensity via optimizing the structure parameters in the SBA beam combination system is proposed. In the proof‐of‐principle nine‐channel SBA beam combination experiment, a low‐modulation near‐field output with an M T value of 1.088 was demonstrated through adjustment, which is nearly identical to the M T value of the incident Stokes seed. This work introduces a promising methodology for achieving high‐pulse energy and high‐average power lasers via SBA beam combining techniques, ensuring exceptional beam quality, which have profound implications for petawatt laser pumping, material processing, and laser‐matter interaction.