In any lasing medium the emission wavelength should be chosen where there is little self absorption. As emission and absorption spectra for metallic vapors did not seem available, therefore, estimates were made of these cross sections for sodium vapor as functions of wavelength. Although absolute values were not obtained, information on where the emission wavelength should occur became evident. The method of obtaining quantities proportional to the cross sections versus wavelength is outlined. A further comparison based on alternative expressions for the absorption and emission cross sections over a limited wavelength range is made.
