Cat's eye echo detecting the damage evolution of silicon induced by 1.06 μm laser

Detecting silicon damage evolution induced by laser irradiation on the focal plane was researched through the change of cat's eye echo. With the time increase of laser irradiation, the echo images started to shake and new texture appeared, which indicate the silicon was damaged. The area of echo images corresponding to the silicon damage expanded unceasingly. The facular structure in the damaged echo image became complicated and the facular area became smaller. The damaged echo image was dynamic stability under the laser irradiation at last. According to the change of echo images, the silicon damage morphology were analyzed. The phenomena of surface oxidation, small scale damage and the expanding of damaged area were observed. The corresponding relationship between the echo image texture feature and the silicon damage morphology was analyzed preliminarly. The correlation and angular second moment would be decreased if the roughness of the damage morphology increased.