Three-dimensional distribution of signal from single monodisperse aerosol particles in a laser induced plasma: Initial measurements

Evidence is provided for a spatial distribution of signal in laser-induced breakdown spectroscopy (LIBS) measurements of single aerosol particles. Monodisperse 1.5-μm diameter silica microspheres are sampled, and particle emission is measured as a function of three-dimensional (3-D) particle location. A combination of scattered-light imaging and spatially resolved spectroscopy is used to determine 3-D particle location. Particle signal is found to be optimized in a region near the major axis of the plasma, on the end of the plasma nearest the incident plasma-forming laser beam. The demonstration of an optimal location for particle signal motivates the development of techniques that account for the effect of particle location to increase measurement precision.