The lineshape of the signals observed by intracavityabsorption in an atomic beam of barium is studied as a function of absorber density. Complex structure is observed consisting of both absorption and enhancement features. Comparison is made with models of intracavityabsorption, and it is concluded that the rate equation model in its present form does not explain the structure. On the other hand the super-regen model does seem able to partially account for the observed structure. The complexity of the lineshape will directly affect those workers who are using intracavityabsorption as a spectroscopic technique.
Kumar, P., Brink, G. O., Spence, S., & Lakkaraju, H. S. (1980). Line shape studies in CW dye laser intracavity absorption. Optics Communications, 32, 129-132. https://doi.org/10.1016/0030-4018(80)90330-2