Monitoring of Atomic Species in Plasma Plumes Using Amplified Spontaneous Emission

The rapid heating of a solid surface due to interaction with a high energy laser beam can lead to vaporization and ionization that generates a plasma plume above the surface. Such plasmas are key elements in material processing techniques such as etching and thin film deposition. Both the process control and the fundamental understanding of these plasmas require diagnostic measurements of various plasma parameters including the concentration of atomic species. For example, during plasma -assisted thin-film deposition the local concentration of atomic species determines the quality of the films deposited. Atomic species concentration can often be high enough to make the plasma optically thick. In such environments, standard diagnostic techniques such as laser-induced fluorescence do not work well. We propose the application of amplified spontaneous emission (ASE) as a diagnostic probe of dense plasmas for the measurement of atomic species concentrations. This technique is applicable in optically dense media and requires only limited optical access. The Phase I effort will result in the development of a diagnostic probe for atomic species concentrations using ASE this probe will be applicable to both government and industrial facilities which generate laser-induced plasma plumes.