利用Q开关Nd:YAG激光器产生的1.06μm倍频后532nm、脉宽10ns的脉冲激光聚焦在置于真空室中铝靶上,观测激光诱导的铝等离子体发射光谱.采用不同的激光能量,分析了波长范围为350nm到400nm的空间、时间分辨发射光谱.在局部热力学平衡(LTE)条件近似下,根据谱线的相对强度,计算得到等离子体电子温度,给出了靶面附近电子温度的空间、时间演化规律;根据谱线半宽,计算等离子体电子密度,并给出了靶面附近电子密度的空间与时间演化规律;在靶面正前方处放置动能探测器,记录粒子飞行时间信号,观测不同激光强度烧蚀铝靶产生等离子体中三种粒子到达探测器的时间,计算得出等离子体中三种观测到的粒子喷射速度.
Using Nd.YAG laser (with a wavelength of 532 nm and a pulse width of 10 ns) ablate aluminum target in Vacuum (2.5 × 10^-2Tort) to observe the emission spectra of plasma. The space-resolved and time-resolved spectra are measured in the wavelength of 350 nm to 400 nm at the different laser energy. Under the model of local thermodynamic equilibrium, space and time characteristics of electron temperature are obtained near the target. The speeds of different particles of plasma induced by pulsed laser ablation of aluminum target are measured. By adjusting laser energy form 10 mJ/pulse to 40 mJ/ pulse, the speed scales and velocity distribution of particles of Al plasma are analyzed.