Transient stimulated Raman scattering in gas mixtures.
We studied, for the first time to our knowledge, transient stimulated Raman scattering in H(2)- D(2) and H(2)- CH(4) gas mixtures excited with 200-fs and 2-ps, 390-nm pulses. Depending on the composition and partial pressure, of those gases, we observed approximately 40 output lines simultaneously. Under optimum conditions a conversion efficiency of as much as 8% in the combination Raman line at 556 nm was obtained in the H(2)- CH(4) gas mixtures. The difference between picosecond and femtosecond pumping is due to self-phase modulation and to generation of a spectral continuum in the latter. Our calculation of the ratio of the partial pressures is in a good agreement with the experimental results. A new method for measuring the unknown Raman scattering cross section of gas molecules is suggested.
Krylov
V
V
Chemistry Department, Swiss Federal Institute of Technology, ETH-Zentrum, CH-8092 Zurich, Switzerland.
Fischer
I
I
Bespalov
V
V
Staselko
D
D
Rebane
A
A