Numerical simulation of modulation to incident laser by submicron to micron surface contaminants on fused silica**Project supported by the National Natural Science Foundation of China (Grant No. 61178018) and the Ph.D. Funding Support Program of Education Ministry of China (Grant No. 20110185110007).

Abstract

Modulation caused by surface/subsurface contaminants is one of the important factors for laser-induced damage of fused silica. In this work, a three-dimensional finite-difference time-domain (3D-FDTD) method is employed to simulate the electric field intensity distribution in the vicinity of particulate contaminants on fused silica surface. The simulated results reveal that the contaminant on both the input and output surfaces plays an important role in the electric field modulation of the incident laser. The influences of the shape, size, embedded depth, dielectric constant (εr), and the number of contaminant particles on the electric field distribution are discussed in detail. Meanwhile, the corresponding physical mechanism is analyzed theoretically.