Applications of Laser-Induced Fluorescence Spectroscopy for Combustion and Plasma Diagnostics

Laser-induced fluorescence spectroscopy is a sensitive and powerful technique for detecting molecules and atoms, measuring species concentrations and energy-level population distributions, and for probing energy transfer processes in molecules and atoms. This chapter reviews the principles of laser-induced fluorescence (LIF). In an LIF measurement, molecules are typically excited from ground electronic levels to excited electronic levels by absorption of laser radiation. One of the most successful areas of application of LIF diagnostics has been in combustion. LIF is a powerful tool for studying the complex chemistry and structure of combustion flows. LIF has been used to measure both flame temperature and the concentrations of reactive intermediates and pollutant species. LIF temperature measurements in flames, along with other temperature-measurement techniques, were recently reviewed by Elder and Winefordner. LIF has found wide application in chemical physics as a monitor of specific quantum states of molecules during energy transfer processes or chemical reactions.