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为了理解前后表面损伤不对称性的物理内涵,利用阴影成像技术研究了纳秒紫外激光诱使熔石英光学元件表面损伤的时间分辨动力学过程.研究表明,纳秒紫外激光与熔石英作用过程中前后表面损伤的物理机理是完全不同的.前表面处空气中等离子体和冲击波较强,等离子体的屏蔽作用抑制了余脉冲能量的沉积,降低了元件损伤程度.而后表面处等离子体吸收激光能量膨胀,对后表面冲击作用更为严重,形成的等离子体电子密度可达到1023cm-3以上,反射部分激光能量与入射的激光余脉冲干涉,使得损伤更为严重.研究结果对理解损伤的机理有重要意义.
In order to understand the physical connotation of the surface damage asymmetry, the time-resolved kinetics of surface damage induced by nanosecond laser induced by nanosecond laser was studied by using shadow imaging technique. The results show that nanosecond laser and fused quartz The physical mechanism of front and back surface damage is quite different. The plasma and shock wave in the air at the front surface is strong, and the shielding effect of plasma suppresses the deposition of the residual pulse energy and reduces the damage of the device, while the plasma at the back surface absorbs the laser energy And the impact on the back surface is more serious. The density of the formed plasma can reach over 1023cm-3, and the laser energy of the reflected part interferes with the incident laser pulse to make the damage more serious. The research results are helpful to understand the damage Significance.