He X N, Hu W, Li C M, Guo L B, Lu Y F
Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0511 USA.
Opt Express. 2011 May 23;19(11):10997-1006. doi: 10.1364/OE.19.010997.
Improved spectral resolutions were achieved in laser-induced breakdown spectroscopy (LIBS) through generation of high-temperature and low-density plasmas. A first pulse from a KrF excimer laser was used to produce particles by perpendicularly irradiating targets in air. A second pulse from a 532 nm Nd:YAG laser was introduced parallel to the sample surface to reablate the particles. Optical scattering from the first-pulse plasmas was imaged to elucidate particle formation in the plasmas. Narrower line widths (full width at half maximums: FWHMs) and weaker self-absorption were observed from time-integrated LIBS spectra. Estimation of plasma temperatures and densities indicates that high temperature and low density can be achieved simultaneously in plasmas to improve LIBS resolutions.
通过产生高温低密度等离子体，激光诱导击穿光谱法（LIBS）实现了更高的光谱分辨率。来自KrF准分子激光器的第一个脉冲用于通过在空气中垂直照射靶材来产生颗粒。来自532 nm Nd:YAG激光器的第二个脉冲平行于样品表面引入，以再次烧蚀颗粒。对第一个脉冲等离子体的光散射进行成像，以阐明等离子体中颗粒的形成。从时间分辨LIBS光谱中观察到更窄的线宽（半高全宽：FWHM）和较弱的自吸收。等离子体温度和密度的估计表明，在等离子体中可以同时实现高温和低密度，以提高LIBS分辨率。
