Laser air plasma expansion by microwaves

Abstract

Utilizing microlasers and microwaves, our study examined the impact of microwaves on the expansion of air plasma. We applied microwaves to the air plasma generated by a microlaser, visualized its growth using a phone camera, and recorded plasma emissions using a high-resolution spectrometer. Software tools were then used to analyze these emissions for temperature changes and electron density. Notably, we noticed a 400-fold increase in plasma volume due to microwave enhancement, even though the microlaser operated at a modest energy level of 1 mJ. Simultaneously, we recorded an increase in temperature and a decrease in electron density when the plasma was subjected to microwaves, indicative of nonequilibrium plasmas. Further, a minor shift in electron temperature during microwave exposure pointed toward the ability of microwaves to sustain plasma characteristics over time. These findings suggest that the microwave application potentially improves the analytical performance of laser-induced breakdown spectroscopy.