Optical analytical technique for carbonaceous particles using laser-induced electro-avalanche fluorescence and laser-induced incandescence

This report describes an optical sensing system for fine particle detection using a combination of two techniques: laser-induced breakdown spectroscopy (LIBS) and laserinduced incandescence (LII). We have improved laser measurement systems applied for small-particle analysis. We have determined elemental composition and density of particles using LIBS and have been able to measure particle size using LII. Controlling the power density of the light source of the present system allowed switching from LIBS to LII. LII temporal analysis was conducted using a streak camera, which was also used for LIBS analysis. The LII technique allows in situ measurement of the average primary particle size of nanoscale soot particles.