The State Key Lab of
High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics, Chinese Academy of Sciences
中 国 科 学 院 上 海 硅 酸 盐 研 究 所 高 性 能 陶 瓷 和 超 微 结 构 国 家 重 点 实 验 室
Tracking and Understanding Laser Damage Events
Laser damage of optical elements in high power laser systems is a longstanding problem since the invention of first laser. Driven by construction of high power laser facilities all over the world, laser damage researches are in a long period of prosperity in the past fifty years. The basic damage mechanisms, thermal and nonlinear damage, established in 1970s told us the story of laser damage events, but laser damage problems are still challenging the laser community and industrials as the laser power grows higher and higher with the developments of the laser technologies. Furthermore, the micro-defects initiating thermal damage depend on the fabrication processes of various optical elements. The comprehensive metrologies were developed to track the origin of the micro-defects come along with fabrications. The influences of defects were analysed, and optimization of fabrication processing and the post treatment measures were adopted to relieve damage. However, there are lots of laser damage events still puzzled us, especially for the UV wavelength or the ultra-short pulse laser. The damage events usually appeared as very small pits or pinpoints which may correlate to nanoscale damage precursors. Unfortunately, it is difficult to detect nano-precursors by traditional optical measures because the precursors are optical invisible for most cases. Novel methods were developed to retrieve the characteristics of the precursors.
Yuanan Zhao is a Professor at Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P R China. In 2005, he received a doctorate in Optical Engineering from Graduate school of Chinese Academy of Sciences. Since then, he worked on laser damage of optics in high power lasers and metrologies for high quality laser optics.