Abstract

Experimental and theoretical studies of stimulated Raman scattering (SRS) involving temporal and/or spatial incoherence are reviewed. In the case of a transform-limited (in space and time) pump pulse, SRS may be generated either coherently or incoherently, depending on the geometry of the interaction volume and on the rate of collisional dephasing. Spatial coherence is governed by the Fresnel number of the volume, while temporal coherence is governed by the average number of collisions occurring within the Stokes pulse duration. These coherences manifest themselves in the pulse-energy probability distribution of Stokes pulses.¹ In the case of a pump pulse that is diffraction-limited but is multimode in frequency, the generated Stokes pulse has intensity modulations that are correlated to those of the pump pulse. The degree of correlation depends on the average number of collisions occurring during a single intensity fluctuation (i.e., ratio of Raman linewidth to laser bandwidth).²

© 1986 Optical Society of America