Additional measurements of the critical absorption coefficient and the anti-Stokes shift of light backscattered from absorbing solutions illuminated by a giant-pulse ruby laser are presented. Frequency shifts of less than the predicted value of one-half the incident linewidth are thought to be due to saturation effects and failure to remove completely the incident light from the interferogram of the backscattered light. The low values of the critical absorption co-efficient observed in several liquids are discussed and measurements of the nonlinear attenuation of some liquids are presented.

• Received 5 August 1968

DOI:https://doi.org/10.1103/PhysRev.175.271