PNNL

Abstract

We demonstrate time-resolved dual-comb spectroscopy of a laser-induced plasma and characterize the temporal evolution of the absorption excitation temperature and population number density for multiple Fe transitions. The spectrum of three excited-state transitions of Fe around 533 nm are simultaneously detected at different time delays following laser ablation of a stainless steel sample. This work probes late-time behavior of laser-induced ablation plumes during plasma cooling, significant for revealing important information on molecule and particle formation. The high spectral resolution and broadband capability of the dual-comb technique, combined with time-resolved measurement capability, will aid in characterization of plasma properties, species identification, and higher resolution spectroscopy including isotopic analysis.