Time-resolved optical resonant absorption spectroscopy of Cr metallic vapor in air using a broadband LED light source

Abstract

In this work, we show the feasibility of applying time-resolved broadband optical absorption spectroscopy using an LED light source as a valuable diagnostic tool for characterizing the electrical arc's current-interruption process. With our setup we have shown the capability of following in a single measurement the time evolution of the diffusion of chromium (Cr) neutral atoms around and after current zero of an electrical arc that was ignited between two Cu–Cr contacts. This is achieved by analyzing the absorption spectrum of CrI resonance lines near the central wavelength of the broadband LED at 425 nm, and using the so-called fast-kinetics acquisition mode of the spectrometer, with a time resolution of 415 µs. As a result, by relying on the optical thinness of our lines, we could estimate the time evolution of the ground-state population of neutral Cr atoms outside the contact gap.