Modulation on incident laser induced by repaired subsurface defect in fused silica

The effect of the repaired subsurface defect with Gaussian profile in fused silica on incident laser is studied according to the scalar diffraction theory. The Matlab simulation results agree with the experiment results. It is shown that modulation on incident laser is produced by the repaired site and varies with the light propagation distance. The modulation may cause damage of the downstream optical components. However, the damage risk can be reduced by installing the downstream optical components at appropriate positions.