Absorption measurements of carbon monoxide laser radiation by water vapor

An intracavity water vapor cell in conjunction with a CO laser was used to measure experimentally the absorptive losses introduced for nineteen of the laser emission lines. The results indicated that the existing theoretical models are inadequate for predicting actual absorptance values for water vapor partial pressures in excess of 100 Torr. The accepted spectral location of at least one water vapor absorption line was shown to be erroneous. A pressure broadening gas such as nitrogen was shown to increase the differential absorptive loss introduced by the water vapor for CO laser rotational lines. This result enhances the applicability of an intracavity water vapor cell as a device for limiting CO laser oscillation to lines having high atmospheric transmission.