Active spectroscopy of excited iron atoms in an erosion laser plasma

The method of coherent anti-Stokes Raman scattering (CARS) was used to probe the plasma of an optical spark formed on the surface of a steel target. Five strong resonances due to transitions between excited states of FeI atoms were recorded in the CARS spectrum. A study was made of the kinetics and polarization properties of the scattered anti-Stokes radiation. The CARS method is recommended for the study of the plasma formed as a result of optical breakdown at solid targets because it can provide a universal means for the analysis of the chemical composition of the targets.