355nm纳秒紫外激光辐照下熔石英前后表面损伤的对比研究  

Comparison of damage between front and rear surfaces under nanosecond 355nm laser irradiation on fused silica

作　　者：刘红婕[1] 周信达[1] 黄进[1] 王凤蕊[1] 蒋晓东[1] 黄竞[1] 吴卫东[1] 郑万国[1] 

机构地区：[1]中国工程物理研究院激光聚变研究中心,绵阳621900

出　　处：《物理学报》2011年第6期453-458,共6页Acta Physica Sinica

基　　金：国家高技术研究发展计划(批准号:2008AA8040508);国家自然科学基金(批准号:20903083)资助的课题~~

摘　　要：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.To investigate the physical mechanism which causes asymmetric damages in front and rear surfaces,time-resolved dynamics of the fused silica＇s surface damage induced by the nanosecond ultraviolet laser is studied using shadow graphic technique.The results show that the damage mechanisms in front and rear surfaces under nanosecond laser interaction with fused silica are absolutely different.Although the plasma and the shock waves in air are relatively high,damage is reduced on the front surface because the plasma shielding limits energy deposition of the remnant pulse.While on the rear surface,two factors aggravate the damage,one comes from the impulsion of the plasma after its absorption of the laser energy,the other comes from the interference between the remnant pulse and the reflected pulse from the plasma.It is instructive to understand the damage mechanism.

关 键 词：熔石英 激光诱使损伤 阴影成像技术 光学元件表面 

分 类 号：TN249[电子电信—物理电子学]