Stimulated light scattering and four-photon processes

R. Barillé, Suren Sogomonian, Genevieve Rivoire

Stimulated Rayleigh-wing scattering is studied here in various liquids excited with a Bessel beam that allows a complete spatial separation between the transmitted exciting light and the scattered light. The results show that a large Stokes spectral band displaying substructures is obtained in the absence of self-focusing, cross-focusing, self-phase modulation, and cross-phase modulation. An interpretation is proposed based on the role of cascade Stokes–anti-Stokes coupled scattering processes.

I. R. Gatland, Louis Gold, John W. Moffat

Guy Mayer, J. Sevin

S O Sapondzhyan, David G. Sarkisyan, G. Torosyan

A phosphate neodymium glass laser emitting picosecond pulses tunable in the 1.05–1.07 μ range was developed to study nonlinear optical processes in atomic barium vapor. Its temporal characteristics were investigated using a modified second harmonic beam method. Electron stimulated Raman scattering and four-photon parametric conversion in atomic barium vapor were used to obtain efficient conversion of the third harmonic of the picosecond phosphate laser (350–356 nm) to the Stokes (580–600 nm) and anti-Stokes (250–253 nm) waves. The highest conversion quantum efficiency for the Stokes wave was 15%. Electron stimulated Raman scattering in an (6 s 2 ) 1 S –(6 s 7 s ) 1 S –(6 s 6 p ) 1 P 0 system, having a strongly forbidden first transition, was recorded for the first time. In the same system, two-photon pumping generated four-photon parametric superradiance and it was found that the signal and idler waves had anomalously broad spectra (wider than 100 cm −1 ).

V. I. Anikin, S V Kryuchkov, V. E. Ogluzdin

An experimental investigation was made of the resonant stimulated electronic Raman scattering near the principal doublet of potassium. A study was made of the dispersion, interaction of two- and three-photon scattering, and influence of four-photon processes. Possible mechanisms of the population of the 4 2 P 1/2 and 4 2 P 3/2 potassium levels were considered. The possibility of phase-matched four-photon parametric interactions in the investigated part of the spectrum was confirmed theoretically.

Iu. M. Kirin, Sergey G. Rautian, Vladimir P. Safonov +1 more