1Department of Precision Instruments and Mechanology, Tsinghua University, Beijing 100084 2Research Center of Laser Fusion, China Academy of Engineering Physics, Sichuan 621900
Abstract：Deuterated potassium dihydrogen phosphate damage performance at 351 nm is studied on a large-aperture laser system. Bulk and rear-surface damage are initiated under the 3$\omega$ fluences of 6.7 J/cm$^{2}$ and 3 J/cm$^{2}$, and show different growth characteristics under multiple laser irradiations with the fluence of 6 J/cm$^{2}$. The size and number of bulk damage keep unchanged once initiated. However, surface damage size also does not grow, while surface damage number increases linearly with laser shots. Different damage thresholds and growth behaviors suggest different formations of bulk and surface damage precursors. The cause of surface damage is supposed to be near-surface absorbing particles buried under the sol-gel coating.
2016, Vol. 33 
