Feasibility of measuring temperature and density fluctuations in air using laser-induced O<inf>2</inf>fluorescence

Abstract

A tunable line-narrowed ArF laser can selectively excite several rotational lines of the Schumann-Runge band system of O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> in air. The resulting ultraviolet fluorescence can be monitored at 90° to the laser beam axis, permitting space and time resolved observation of density and temperature fluctuations in turbulence. Experiments and calculations show that ± 1 K, ± 1 percent density, 1 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> spatial, and 1 μs temporal resolution can be achieved simultaneously under some conditions.