Near-IR bromine Laser Induced Breakdown Spectroscopy detection and ambient gas effects on emission line asymmetric Stark broadening and shift

摘要

Investigation via Laser-Induced Breakdown Spectroscopy of a near-infrared bromine emission line (827.2 nm) with an UltraViolet ablation laser and a gated detector is reported.The effects of ambient pressure and gas species (air,O_2,N_2 and He) on the atomic emission line strength and spectral profile were systematically investigated.Substantially improved signal strength and reduced background radiation are demonstrated near 100 mbar ambient pressure with all gases.Optimal results were achieved when helium was used.Asymmetric broadening and shift of the 827.2 nm bromine line,attributed to pressure-dependent Stark effect has been revealed.This effect is prominent when air,oxygen or nitrogen are present and is much less manifested when helium is used.Possible interpretations of this effect are presented.