环境气体对激光诱导Al等离子体光谱的影响

Effect of ambient gas to the spectral distribution of laser-produced Al plasma

调QNd :YAG脉冲激光 (波长 1.0 6 μm ,脉冲宽度 10ns,能量 42mj/pulse)烧蚀平面Al靶 ,在垂直靶面方向 ,利用光学多道分析系统 (OMA) ,测量了激光诱导产生的等离子体发射光谱分别在环境气体为Air,N2和Ar,气压范围分别在 10 -2 Torr ,15 2Torr,30 4Torr,5 32Torr和 76 0Torr下的空间分布。实验表明 ,随着环境气体压强的增大 ,光谱的空间分布被压缩 ,且谱线强度的峰值向靶面方向移动 ;在相同的气压下 ,Ar环境下产生的光谱强度明显大于在Air和N2 环境下产生的光谱强度 ;在气压为 15 2Torr的不同环境气体下 ,均发现光谱在离靶面很近的地方 (约 0 .5mm～ 1.0mm)减小 ,甚至消失 ;在Ar环境气体下 ,谱线 396 .1nmAlⅠ的空间分布随着与靶面距离的增大 ,谱线位置向短波方向有约 0 .0 3nm (对应OMA探头的一个二极管阵列 )的移动 ,而谱线 394.4nmAlⅠ的移动不太明显。

Q switch Nd:YAG laser(wavelength 1.06 μm, pulse width 10 ns, energy 42 mj/pulse) was used to ablate plane solid Al target in different ambient gas. Using optical multichannel analysis system, the laser produced Al plasma emission spectra has been recorded as a function of distance from target. The emission characteristics in Air, N 2 and Ar atomsphere are found to depend strongly on the nature and pressure of the surrounding gas. It has been observed that the peak of spectra intensity is compressed and move to target surface when pressure increases, stronger plasmas are formed in an Ar atmosphere rather than in nitrogen and air, meanwhile, the spectra shift in Ar surrounding gas at high pressure is diecovered in a small scale.