Laser-Induced Plasma Based Diagnostics

University Of Florida, Gainesville FL

Investigators

Abstract

Project Summary The objective of this research is the understanding of the physical processes associated with the interactions of laser-induced plasmas with aerosol particles. The emphasis is on the basic plasma-particle interactions, a complex problem given the highly transient nature of the laser-induced plasma, plasma non-homogeneity, and the uncertainty as to the exact mechanisms of aerosol particle dissociation. To elucidate the plasma science coupled to each of these problems, a program is executed consisting of the following: (1) the design and implementation of a laser-induced plasma spectroscopy apparatus coupled with an electrostatic particle trap; this novel experimental facility will enable the manipulation of individual submicron- to micron-sized particles to realize spatially resolved measurements of their interaction with laser-induced plasmas; (2) a comprehensive experimental investigation of the laser-induced plasma-particle interactions, including time-resolved measurements of the particle dissociation processes and subsequent atomic diffusion processes; and (3) the formulation of optimal laser-induced plasma excitation and atomic emission diagnostic schemes to improve laser-induced plasma spectroscopy (LIPS) as an analytical technique based on the fundamental plasma processes elucidated in the proposed experimental program. This effort addresses such areas as plasmas in environmental science and plasma diagnostics. Laser-induced plasma spectroscopy (LIPS) has become an important contemporary analytical tool due to the relative simplicity of the technique, the availability of robust electro-optic components, and the current interest in real-time analytical tools in environmental and process monitoring. In particular, recent interest in health risks and mortality associated with ambient-air particulate matter has led to demands for advanced real-time instrumentation for fine particulate analysis. Laser-induced plasma spectroscopy is an ideal candidate for this. However, many questions remain regarding the interactions of laser-induced plasmas with fine aerosol particles, including particle vaporization/dissociation, atomic diffusion of aerosol constituent atoms, and ensuing plasma optical emission. This program directly addresses these key issues. Broader impact In addition to the experimental research program in plasma science, the proposed research also functions to educate and train engineering students in the important crosscutting fields of advanced measurement techniques and plasma science. Such educational objectives are accomplished through graduate research, undergraduate research, and significant incorporation of research elements into the engineering curriculum.