Optical pumping of CO by a convective flow CO laser

A convectively cooled CO laser has been used to optically pump the vibrational distribution of CO preheated in a dc discharge. For maximum pump flux levels of 8 kW/sq cm, it was found that optical coupling to flowing CO could be achieved only in the presence of discharge preheating, and that the extent of optical pumping was a strong function of pump wavelength over the range 5.0-5.1 microns. The excited CO vibrational distribution was derived by spectroscopic analysis to be similar to the highly nonequilibrium distributions obtained in prior work. Numerical calculations of the vibrational distributions have been performed, and reasonable agreement with the experimental results was found.