<title>Laboratory measurements of atmospheric water vapor and aerosol absorption at 1.064 um</title>

Abstract

We report the use of a windowless resonant spectrophone to make highly sensitive (10-9 cm-1) photoacoustic measurements of atmospheric water vapor and aerosol absorption. A tunable high-resolution cw Nd:YAG laser was used to measure the water vapor lines and aerosol absorption spectrum at 1.064 mm. The water vapor absorption lines were used to calibrate the spectrophone for the aerosol measurements. The spectrophone was also calibrated using the theoretical expression with an independent measurement of the Q of the spectrophone. The initial windowless spectrophone has the ability to make in situ real- time measurements of atmospheric absorption to an accuracy sufficient for thermal blooming calculations. The ability of the spectrophone to detect at the 40-parts-per-trillion-level of other gaseous and volatile species is discussed. The use of resonant mufflers to isolate the spectrophone from external noise is also presented.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.