Author Affiliations
Abstract
1 East China Normal University, State Key Laboratory of Precision Spectroscopy, Shanghai, China
2 Chongqing Institute of East China Normal University, Chongqing, China
3 Jinan Institute of Quantum Technology, Jinan, China
Laser-induced breakdown spectroscopy (LIBS) is a useful tool for determination of elements in solids, liquids, and gases. For nanosecond LIBS (ns-LIBS), the plasma shielding effect limits its reproducibility, repeatability, and signal-to-noise ratios. Although femtosecond laser filament induced breakdown spectroscopy (FIBS) has no plasma shielding effects, the power density clamping inside the filaments limits the measurement sensitivity. We propose and demonstrate plasma-grating-induced breakdown spectroscopy (GIBS). The technique relies on a plasma excitation source—a plasma grating generated by the interference of two noncollinear femtosecond filaments. We demonstrate that GIBS can overcome the limitations of standard techniques such as ns-LIBS and FIBS. Signal intensity enhancement with GIBS is observed to be greater than 3 times that of FIBS. The matrix effect is also significantly reduced with GIBS, by virtue of the high power and electron density of the plasma grating, demonstrating great potential for analyzing samples with complex matrix.
femtosecond filament plasma grating induced breakdown spectroscopy high power and electron density enhancement matrix effect Advanced Photonics
2020, 2(6): 065001
1 中国科学院上海光学精密机械研究所强场激光物理国家重点实验室, 上海 201800
2 中国科学院大学, 北京 100049
3 上海交通大学聚变科学与应用协同创新中心, 上海 200240
4 上海师范大学物理系, 上海 200234
5 中国科学院大气物理研究所中层大气和全球环境探测重点开放实验室, 北京 100029
6 拉瓦尔大学光学、光子学和激光研究中心, 加拿大 魁北克市 G1V 0A6
在室温条件下的小型云室中,研究了不同参数对飞秒激光诱导较大尺寸气溶胶生成的影响。实验结果表明,在亚饱和条件下,随着环境相对湿度的提高,不同尺寸气溶胶的数密度增大,尺寸分布以0.3~0.5 μm为主;当环境相对湿度达到近饱和条件时,较大尺寸(直径D≥0.7 μm)气溶胶的数密度显著增大,1.0~2.0 μm气溶胶与0.3~0.5 μm气溶胶的数密度可相比拟。此时,通过延长激光照射时间或者缩紧激光聚焦条件,不同尺寸气溶胶的数密度可同等程度地增大,尺寸分布规律基本不变。理论分析结果表明,环境相对湿度条件是制约飞秒激光诱导较大尺寸气溶胶生成的关键因素。
超快光学 非线性光学 飞秒光丝 气溶胶 光化学反应
