形状与位置对断点划痕场分布的影响研究

摘要

Elliptic paraboloid model is established, and three-dimensional finite-difference time-domain method has been employed to sim- ulate the field distribution of discontinuous crack with different shapes and positions in fused silica output subsurface under 355 nm laser incidence. Results show that both electric field intensity and the number of enhanced points （with ｜E｜ ≥ 2.0 V/m） follow a trend of first increasing and then decreasing with the increase of collinear axis length of ellipsoid. The light intensity enhancement factor reaches a maximal value when the axial ratio is 1.1 to 1.2. If parallel collinear axis length of ellipsoid increases, the electric field intensity first increases gradually, and then becomes stable when the axial ratio is 0.53. At the same time, the number of enhanced points grows rapidly.%用3维时域有限差分方法分别研究了在355nm入射激光作用下，熔石英后表面具有不同形状和位置的断点划痕对场分布的影响．研究表明，对于椭圆状的坑点，当共线的轴长逐渐增大时，电场幅值与强点数目先增大后减小，获得最大光强增强因子的两轴比是1．1—1．2，此时坑点呈近圆形．当平行的轴长逐步增大时，电场幅值先逐渐增大，当两轴比为0．53时趋于平缓，而强点总数则呈“J”形曲线不断增长．当坑点尺寸相同但排放位置不同时，相邻坑点的相对面积愈大，调制愈强．