Investigations of Molecular Emission from Laser Ablation Plumes Interacting with Background Gases of Varying Density

Laser ablation of solid targets provides a versatile platform for investigating the interplay between molecular spectral emission and fluid dynamic properties of low-temperature plasmas. To this end, we have developed an experimental apparatus capable of measuring the plasma plume${'}$s spatial- and temporal-evolution in a controlled environment. Changes in molecular emission were recorded as a function of changing the Reynolds number of the background gas by varying gas pressure and species. In the experiments, time-gated molecular spectra were measured from plumes produced from low- to mid-Z targets with laser intensities ranging from 10$^{7}$ to 10$^{11}$ W/cm$^{2}$. The experimental results will be discussed within the framework of radiation hydrodynamic models being developed to describe these complex plasma phenomena.