“SSD scattering signal extraction in LSCT”

Sub-Surface Damage (SSD) in optical element had became a shackle of research and manufacture in energy, advanced technology and so on, for its severe influence to the laser-induced damage threshold, the long term stability of large optical system. So the evaluation of SSD was a hot topic in optical engineering. The scattering caused by optical component SSD links the optical non-destructive evaluation and SSD itself. Laser scanning confocal technology (LSCT) is an effective way for SSD assessment and it is also based on the back scattering of SSD. The scattering signal extraction is the key point in SSD measurement using LSCT. The difficulty of SSD signal extraction is introduced firstly. The signal composition accepted by LSCT detector is analysed in detail. The different component part is successively and independently analysed, and the elimination or reduction way of each part is given. Lastly, the high SNR SSD scattering signal of one element tested by LSCT equipment is displayed in 2D figure.