环境气氛压强对熔石英紫外激光损伤阈值的影响

 利用1∶1, S∶1, R∶1方法，测试了不同真空度（10-3～105 Pa）和不同气氛（空气、氮气、氧气）环境下熔石英351 nm激光损伤阈值，测试结果表明,用1∶1, S∶1方法测试得到的阈值在不同气氛压强下几乎相等；R∶1损伤阈值受气压的影响较大，在小于等于10³ Pa气压下，较105 Pa气压的阈值降低28%～41%；但R∶1损伤阈值同气氛的关系不大，在同气压下差别小于10%，在测量值误差范围内。利用50%破坏几率对应的损伤阈值Fth（R∶1）一半的激光能量密度辐照样品，考察其抗多脉冲辐照的能力，分析表明，在同样的能量密度辐照下，10³ Pa空气及氮气环境和105 Pa氮气环境下同样具有高的寿命；而10^-3 Pa高真空环境下其寿命较短，在10^-1 Pa低真空环境下其寿命最短。

Effect of gas atmosphere and pressure on 351 nm laser-induced damage threshold of fused silica

S∶1, 1∶1 and R∶1 laser damage tests for fused silica were performed under different gas atmosphere (air, O2, N2) and pressures (10-3~105 Pa) with 351 nm Nd:YLF laser. The results show that laser-induced damage threshold(LIDT) via 1∶1 and S∶1 tests are almost the same in different gas atmosphere and pressures. The LIDT via R∶1 tests are more liable to pressure than gas atmosphere. The R∶1 threshold of fused silica under pressures lower than 103 Pa decrease by 28%~41% compared with that at 105 Pa. Under equal pressure but different gas atmosphere the R∶1 threshold has less than 10% deviation, which is within the measurement error. The multi-pulse irradiation resistant property for different gas atmosphere and pressures were also studied under irradiation of half of the damage thresho