Influence of the population change on the stimulated Raman scattering by short light pulses

Nikolai V Kravtsov, Nikolai I Naumkin, V P Protasov

An investigation was made of the dynamics of stimulated Raman scattering (SRS) in compressed hydrogen excited by a train of short pulses. The observed features of the SRS dynamics were attributed to the competition between the focusing influence of an SRS lens and the defocusing influence of a thermal lens generated as a result of relaxation of an excited state. The method employed made it possible to determine the polarizability of the vibrational state of the molecules excited by SRS.

S. Ya. Kilin, Marek Trippenbach, J. Cooper

N. V. Okladnikov, Vladislav V Zverev, Galina L. Brekhovskikh +1 more

An investigation was made of the influence of the geometric excitation conditions on the energy dependences of the stimulated scattering of focused laser pulses of ~ 10 −8 sec duration when the sharpness and depth of focusing were varied. The experimental results obtained in this study were interpreted theoretically on the basis of a quantum analysis of stimulated Raman scattering in a two-level system. The experimental relationships could be explained only if an allowance was made for the changes in the populations of the levels participating in the Raman transition. It was possible to select the experimental conditions so that reconstruction of the wavefront of the pump radiation was observed under stimulated scattering conditions in a wide energy range.

V. A. Zubov, M. M. Sushchinskiǐ, I. K. Shuvalov

Marshall Rogers, Stephen Schiller, Yuri V. Rostovtsev

Richard Wunderlich, Moore, W. R. Garrett +1 more

Secondary nonlinear optical effects following parametric four wave mixing in sodium vapor are investigated. The generated ultraviolet radiation induces stimulated Raman scattering and other four wave mixing process. Population transfer due to Raman transitions strongly influences the phase matching conditions for the primary mixing process. Pulse shortening and a reduction in conversion efficiency are observed. 8 refs., 3 figs.