Hao Zhongqi, Deng Zhiwei, Liu Li, Shi Jiulin, He Xingdao
School of Measuring and Optoelectronic Engineering, Nanchang Hangkong University, Nanchang, 330063, China.
Key Laboratory of Opto-electronic Information Science and Technology of Jiangxi Province, Nanchang Hangkong University, Nanchang, 330063, China.
Front Optoelectron. 2022 Apr 28;15(1):17. doi: 10.1007/s12200-022-00020-9.
Spatial confinement is a simple and cost-effective method for enhancing signal intensity and improving the detection sensitivity of laser-induced breakdown spectroscopy (LIBS). However, the spatial confinement effects of LIBS under different pressures remains a question to be studied, because the pressure of the ambient gas has a significant influence on the temporal and spatial evolution of plasma. In this study, spatial confinement effects of LIBS under a series of reduced air pressures were investigated experimentally, and the plasma characteristics under different air pressures were studied. The results show that the reduced air pressure can lead to both earlier onset and weakening of the enhancement effect of the spatial confinement on the LIBS line intensity. When the air pressure drops to 0.1 kPa, the enhancement effect of the emission intensity no longer comes from the compression of the reflected shock wave on the plasma, but from the cavity's restriction of the plasma expansion space. In conclusion, the enhancement effect of spatial confinement technology on the LIBS is still effective when the pressure is reduced, which further expands the research and application field of spatial confinement technology.
空间限制是一种增强激光诱导击穿光谱（LIBS）信号强度和提高检测灵敏度的简单且经济高效的方法。然而，不同压力下LIBS的空间限制效应仍是一个有待研究的问题，因为环境气体的压力对等离子体的时间和空间演化有显著影响。在本研究中，实验研究了一系列降低气压下LIBS的空间限制效应，并研究了不同气压下的等离子体特性。结果表明，降低气压会导致空间限制对LIBS谱线强度增强效应的起始时间提前且减弱。当气压降至0.1 kPa时，发射强度的增强效应不再来自反射冲击波对等离子体的压缩，而是来自腔体对等离子体膨胀空间的限制。总之，在压力降低时，空间限制技术对LIBS的增强效应仍然有效，这进一步拓展了空间限制技术的研究和应用领域。
