Ultraviolet filtered Rayleigh scattering temperature measurements with a mercury filter

We report the development of ultraviolet filtered Rayleigh scattering as a diagnostic tool for measurements of gas properties. A frequency-tripled nar row-linewidth Ti:sapphire laser illuminates a sample, and Rayleigh scattere d light is imaged through a mercury-vapor absorption filter. Working in the ultraviolet improves the signal-to-noise ratio compared with that previous ly obtained in the visible as the result of an enhanced scattering cross se ction as well as the nearly ideal properties of the mercury filter. Tuning the laser through the absorption notch of the filter is a means of probing the scattering line shape, which contains temperature information. Temperat ure measurements of air are shown to have uncertainties of less than 3%. (C ) 1999 Optical Society of America.