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

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 mu s. 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.