激光诱导Al等离子体温度的测定及时间变化特性研究

Measurement of laser-produced Al plasmas temperature at different delay time

利用YAG激光烧蚀Al靶产生 3条AlⅢ等离子体谱线 (4 52 92 ,4 51 2 5,4 15 0 1nm) .在局部热力学平衡近似下 ,测试得到 :在激光能量为 37mJ/pulse时 ,等离子体电子温度在 150 0 0K附近抖动 ,且随延迟时间无明显变化 ;在激光能量为 6 2mJ/pulse下 ,电子温度上升至 1750 0K附近 ,但随延迟时间有较为明显的波动现象 .利用玻尔兹曼图 ,测得AlⅢ谱线 4 4 7 99nm (4f2 F7/2 — 5g2 G9/2 )跃迁的几率约为 (10 4± 0 8)× 10 8s-1.

The temperature of Al laser produced plasmas(LPP)have been measured at different delay time and laser energy.Using the model of local thermodynamic equilibrium(LTE),the electron temperature at 37?mJ/pulse of laser energy was about 15?000?K.In different delay time,the temperatures did not have obvious change,but quiver phenomena have been observed.At 62?mJ/pulse of laser energy,the temperature increased to about 17?500?K,and some fluctuating phenomena were tested.Meanwhile,the transition probability of 447 99?nm line of AlⅢ was measured by the Boltzmann plots was about(10 4±0 8)×10 8s -1 .