Investigation of high power laser coatings

High laser2induced damage threshold and large aperture were focuses on the studies of high power laser coat2 ings. This paper report s the research activities at our center. Several measures were developed for evaluating characters of laser damage , including determination of laser induced damage threshold and detection of absorption based on surface thermal lensing technique. Defect was deemed to be the initial source of laser damage , and was the main factor rest ricting the laser damage resistance of optical coatings. The contribution of several kinds of typical defect s to laser damage was an2 alyzed , and some deposition measures were adopted to control and eliminate the origin of defect . Furthermore , some post2 t reatment methods were also employed to alleviate the influence of the defect and to improve the laser damage resistance. Correction mask was int roduced to improve the thickness uniformity , and the thickness uniformity can be amended to less than 1 % in the range of Φ650 mm. Preliminary investigation related to surface deformation was also conducted.