Stimulated Concentration Scattering in the Binary-Gas Mixtures Xe-He and SF6-He

The frequency shift of the backscattered light, stimulated by an intense ruby-laser beam, has been measured in mixtures of 5 atm of S${\mathrm{F}}_6$ and 0-50 atm of He, and also in mixtures of 8 atm of Xe and 0-80 atm of He. For relative He concentrations less than 60%, the frequency is characteristic of stimulated Brillouin scattering. Above 60% He concentration, a rapid decrease in the frequency shift takes place characteristic of stimulated concentration scattering. Good agreement is obtained with the theory and also with recent data on spontaneous concentration scattering in the same gas mixtures.