›› 2014, Vol. 23 ›› Issue (8): 87702-087702.doi: 10.1088/1674-1056/23/8/087702
• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇 下一篇
肖勇a, 陈明君a, 程健a, 廖威b, 王海军b, 李明全a
Xiao Yong (肖勇)a, Chen Ming-Jun (陈明君)a, Cheng Jian (程健)a, Liao Wei (廖威)b, Wang Hai-Jun (王海军)b, Li Ming-Quan (李明全)a
摘要: KH2PO4 (KDP) crystal with excellent optical properties is a very important element of inertial confinement fusion (ICF) device. However, KDP crystal surface micro-defects severely reduce the crystal laser damage threshold, affecting the crystal service life. In this paper, Gaussian repaired pit is used to replace the crystal surface micro-defects, in order to improve the laser damage resistance of the KDP crystal with surface micro-defects. At first, the physical model of Gaussian repaired pit is built by Fourier model method, and the accuracy of the method is analyzed. It is found that the calculation error can be reduced by increasing the product of the width-period ratio and the truncation constant of the repaired pit. The calculation results about the physical model of Gaussian repaired pit show that the light intensity distribution within the crystal is symmetrical, and there are evidently enhanced light intensity regions in the crystal. Meanwhile, the maximum relative intensity inside the KDP crystal decreases gradually with the increase of the width of the Gaussian repaired pit. Secondly, the Gaussian repaired pits with different widths and the same depth of 20 μm are processed by micro-milling. Their surfaces are very smooth and present the ductile cutting state under the microscope. Finally, the laser damage threshold of the Gaussian repaired pits on the surface of the KDP crystal sample is measured by a 3ω, 6-ns laser. The results show that the maximum threshold of the Gaussian repaired pits is 3.12 J/cm2, which is 60% higher than the threshold of initial damage point, and the laser damage threshold increases with the increase of the width of the Gaussian repaired pit.
中图分类号: (KDP- and TGS-type crystals)