Influence of target temperature on H alpha line of laser-induced silicon plasma in air

Abstract

This study mainly discusses the effect of target temperature on the emission intensity of the H alpha line in laser-induced silicon plasma in an atmospheric environment. The sample was uniformly heated to temperatures ranging from room temperature (22 °C) to a high temperature (300 °C) with laser energy ranging from 5.5 mJ to 11.5 mJ. Emission lines of Si (I), Si (II), and H (I) were observed. The H alpha line was attributable to a small amount of water vapor derived from natural humidity in the surrounding air. The H alpha line was widely used to measure electron density in laser-induced plasma. The results show that an increase in the sample temperature improved the spectral intensity of the Si line, whereas the emission intensity of the H alpha line declined. The reduction in the H alpha line was due to lower air density near the heated target surface. This investigation enhances the understanding of laser-induced breakdown spectroscopy applications at higher sample temperatures.