Influence of polarization of laser beam on emission intensity of femtosecond laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is an important technique which is widely used to analyze element composition. In order to improve the sensitivity of LIBS, much effort has been made to enhance the spectral intensity of LIBS by proposing a number of methods. In addition, we find that laser polarization has great influence on the emission intensity of femtosecond LIBS. By comparing the emission intensity of femtosecond LIBS in the circular polarization with that in the linear polarization, the spectral intensity in the case of circular polarization is stronger than that in the case of linear polarization. Moreover, this phenomenon is more obvious as laser energy increases. The polarization plays an important role in LIBS signal intensity. Based on the observation, the enhanced mechanism of the laser polarization for the spectral intensity is discussed in this paper, which will be helpful in spectral analysis and component analysis. *Project supported by the National Natural Science Foundation of China (Grant Nos. 11674128, 11674124, and 11974138), the Jilin Provincial Scientific and Technological Development Program, China (Grant No. 20170101063JC), and the Scientific and Technological Research Project of the Education Department of Jilin Province, China (Grant No. JJKH20200937KJ).