Optical subsurface damage evaluation using LSCT

The evaluation of subsurface damage (SSD) has become a key problem in optical engineering field. Laser scanning confocal technology (LSCT) is one of the potential SSD non-destructive evaluation (NDE) methods. Under three assumptions, an innovative and credible scattering model, which is to detect subsurface defect through LSCT, is built base on the classical Mie light scattering theory. Aimed to the model, three important parameters are discussed respectively that is N.A., wave length and relatively refraction index. In order to verify the reasonableness of the model, an effective measurement is done for a usual polished optical surface, and the survey result is in accord with the model. At last, several helpful conclusions about subsurface damage assessment using LSCT are given.