MULTIPLEX POLARIZATION SPECTROSCOPY OF OH FOR FLAME THERMOMETRY

Multiplex polarization spectroscopy is demonstrated and applied to the rmometry of a methane/air flame. Using a broad bandwidth, modeless las er, single-shot spectra of OH were recorded showing several transition s from the A(2) Sigma - X-2 Pi(0,0) band system. High resolution polar ization spectra were also recorded in the same flame using a conventio nal, frequency scanned, narrow linewidth dye laser. Absorption effects were found to produce significant systematic errors in the temperatur es derived from the unsaturated spectra produced by both multiplex and narrow linewidth scanning techniques. After correction for absorption effects, temperatures were derived from the single-shot multiplex spe ctra with a precision of 4% which agreed well with values obtained fro m scanned spectra and from the calculated adiabatic temperatures.