Guo L B, Zhang B Y, He X N, Li C M, Zhou Y S, Wu T, Park J B, Zeng X Y, Lu Y F
Wuhan National Laboratory for Optoelectronics (WNLO), College of Optoelectronics Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, China.
Opt Express. 2012 Jan 16;20(2):1436-43. doi: 10.1364/OE.20.001436.
In laser-induced breakdown spectroscopy (LIBS), a pair of aluminum-plate walls were used to spatially confine the plasmas produced in air by a first laser pulse (KrF excimer laser) from chromium (Cr) targets with a second laser pulse (Nd:YAG laser at 532 nm, 360 mJ/pulse) introduced parallel to the sample surface to re-excite the plasmas. Optical emission enhancement was achieved by combing the spatial confinement and dual-pulse LIBS (DP-LIBS), and then optimized by adjusting the distance between the two walls and the interpulse delay time between both laser pulses. A significant enhancement factor of 168.6 for the emission intensity of the Cr lines was obtained at an excimer laser fluence of 5.6 J/cm(2) using the combined spatial confinement and DP-LIBS, as compared with an enhancement factor of 106.1 was obtained with DP-LIBS only. The enhancement mechanisms based on shock wave theory and reheating in DP-LIBS are discussed.
在激光诱导击穿光谱法（LIBS）中，使用一对铝板壁在空间上限制由来自铬（Cr）靶的第一个激光脉冲（KrF准分子激光器）在空气中产生的等离子体，同时引入第二个与样品表面平行的激光脉冲（532nm的Nd:YAG激光器，360mJ/脉冲）来重新激发等离子体。通过结合空间限制和双脉冲LIBS（DP-LIBS）实现了光发射增强，然后通过调整两壁之间的距离和两个激光脉冲之间的脉冲间隔时间进行优化。与仅使用DP-LIBS获得的增强因子106.1相比，在准分子激光能量密度为5.6J/cm²时，使用组合的空间限制和DP-LIBS获得了Cr线发射强度的显著增强因子168.6。讨论了基于冲击波理论和DP-LIBS中的再加热的增强机制。
