Experimental impact of picosecond laser pulse duration on plasma electron density and temperature investigated through laser-induced breakdown spectroscopy

This study introduces a novel approach that utilizes picosecond laser-induced breakdown spectroscopy (Ps-LIBS) to precisely control plasma parameters for enhanced elemental analysis. The electron density and temperature of aluminum plasma generated in air at atmospheric pressure can be effectively modulated by varying the duration of the Q-switched Nd: YAG 1064 nm picosecond laser pulse between 500 and 170 picoseconds. Measurements of plasma parameters are performed under local thermodynamic equilibrium (LTE) conditions that are verified with attention to the effect of plasma self-absorption and its corrections. Our results show that increasing the pulse duration increases the plasma electron density from 1.25 × 10 17 to 1.56 × 10 17 cm −3 ± 2.9% and the electron temperature from 6080 to 7190 ± 10% K, confirming the role of plasma shielding. These findings clarify the relationship between laser pulse duration and plasma characteristics, addressing discrepancies in prior studies. This precise control of plasma parameters enables tailored applications in material processing, environmental monitoring, and plasma-based technologies, thereby advancing Ps-LIBS’s capabilities for elemental diagnostics and materials science.