STIMULATED RAMAN-SCATTERING - DIFFRACTIVE COUPLING IN TRANSIENT AND STEADY-STATE REGIMES

A numerical study is presented of the steady-state and transient regimes in stimulated Raman scattering, including diffractive coupling of the fields and detuning of the Stokes field from resonance. In the steady-state regime, ring formation in the laser output intensity is observed as well as a ring in the Stokes output intensity when it is detuned from resonance. In the transient regime a solitonlike pulse is initiated by modulation of the phase of the input Stokes field. For Fresnel numbers between 5 and 50, we observe a simultaneous maximum of the on-axis laser and Stokes intensities after a pi phase shift is introduced on the Stokes seed. At the same time the transverse profiles of the fields are narrowed and the laser intensity displays a satellite ring. It is found that the soliton remains relatively stable, although diffraction eventually leads to its decay.