建立了熔石英元件修复点交联分布数值模拟模型,利用标量衍射理论结合快速傅里叶变换算法,分析了351 nm激光辐照下修复区域对下游光传输的调制影响。研究结果表明,交联修复区域对下游光传输的调制主要受修复点间交联程度的影响,随着交联程度的增大,调制光场极大值迅速增大后快速减小,其分布位置先逐渐靠近后迅速远离修复元件出光面。光场调制随着传输距离的增大先快速增大后迅速减小。优化交联修复区域形貌结构参数可有效避免下游元件发生级联损伤。

A numerical simulation model based on the cross-linked distribution of mitigated pits in the fused silica elements is proposed. The modulation effect of the mitigation area on the downstream light transport under the 351 nm laser irradiation is studied by the scalar diffraction theory and the fast Fourier transform algorithm. The results indicate that the modulation of the cross-linked mitigation area on the downstream light transport is mainly determined by the cross-linking degree of mitigated pits. With the increase of cross-linking degree, the local maximum of light modulation first increases rapidly and then decreases very fast, and the corresponding location first approaches and then is far away from the output surface of the mitigated element. With the increase of propagation distance, the light modulation first increases rapidly and then decreases very fast. The parameter optimization of the morphological structure of the mitigation area can avoid effectively the cascading damages among the downstream elements.