两级级联分段镜分束器相干合成系统的热致合成性能退化机理研究OA

[Background]In high-power coherent beam combining systems based on segmented-mirror-splitters(SMS),thermal effects arising from parasitic absorption in optical components are critical factors that limit steady-state combining performance.[Purpose]To address the limited understanding of the mechanisms underlying thermally induced performance degradation in high-power two-stage cascaded SMS systems,we established a 28-channel optical-thermal-mechanical multi-physics coupling model using the finite element method.[Methods]Nume-rical simulations were performed to analyze the thermally induced wavefront distortion and the sequential coherent superposition of multiple beams within the zig-zag optical path.[Results]The results indicate that the accumulation of laser power along the combining direction leads to a significantly higher thermal load on the second-stage segmented mirror than on the first stage.Consequently,an asymmetric temperature gradient induces substantial beam quality degradation along the combining direction.[Conclusions]Furthermore,parametric optimization demonstrates that reducing the substrate thickness can effectively suppress thermal distortion,thereby enhancing combining efficiency and improving beam quality.Meanwhile,although increasing the sub-beam spacing reduces thermal effects and enhances combined power,it simultaneously intensifies the anisotropic beam quality degradation.