Consequences of femtosecond laser filament generation conditions in standoff laser induced breakdown spectroscopy

The combination of femtosecond laser filament ablation and emission spectroscopy is a potential analytical tool for standoff characterization of samples of interest. We compare the emission features and physical conditions of plasmas generated from metal targets using either by loosely focused femtosecond filaments or by lens-free filaments. Our results show that the filament generation conditions influence the plasma properties appreciably which include the atomic and molecular emission features, persistence and plasma fundamentals (temperature and density). The loosely focused fs pulse filaments are found to generate ablation plumes with higher temperature and density along with increased persistence compared to plumes generated by lens-free filaments. (C) 2016 Optical Society of America