研究了电场在介质膜光栅结构中的增强效应对其抗激光损伤阈值的影响.使用傅里叶模式方法计算了电场在介质膜光栅浮雕结构内的分布.数值分析表明：电场在介质膜光栅中增强的最大值为入射光的2倍，其最大的位置出现在相对于入射光对面的光栅槽侧壁。实验测试介质膜光栅样品在1 064 nm和12 ns, 51.2°和TE偏振光入射时，其抗激光损伤阈值为6.61 J/cm2.对损伤形貌进行扫描电镜精确分析，发现介质膜光栅的初始损伤产生于电场在介质膜光栅内增强最大的位置处.

The effect of electric field enhancement on laser-induced damage morphology of multi-layer dielectric gratings was investigated. Electric field distribution was calculated by using the Fourier mode method. Numerical treatment shows that the peak electric field occurs at the groove edge opposite to the incident direction by nearly a magnitude of two. Laser-induced damage threshold of 6.61 J/cm2 was obtained for 12 ns pulses at 1 064 nm with TE mode and 51.2° incident. Scanning electron microscopy (SEM) of damage morphology shows that the initial damage occurs from the place where the electric filed is strongly enhanced.