CORRELATIONS BETWEEN THE INTENSITIES OF PUMP, DEPLETED PUMP AND STOKES WAVES IN SUPERBROADBAND STIMULATED RAMAN-SCATTERING

The pair correlations between the intensities of input pump laser radi ation with spectral bandwidth of 250 cm(-1), which has femtosecond and picosecond noise structures, output depleted pump radiation and Stoke s light generated through stimulated Raman scattering (SRS)in compress ed hydrogen have been studied experimentally under weak and strong pum p depletion. The third order correlation functions were measured by me ans of time-delayed four-wave mixing in a Kerr-shutter scheme with two noise light beams under investigation. The data obtained show that th e Stokes wave is well correlated with the input pump wave up to an ene rgy conversion efficiency of about 30%. The measured functions display the considerable suppression of the femtosecond amplitude fluctuation s in the depleted pump beam upon increasing the efficiency of SRS and pump depletion. Such a result shows a possible way for preparing super broadband light with smooth temporal envelope and predominant phase fl uctuations using SRS. The picosecond part of the correlations between the depleted pump and Stokes waves is characterized by the asymmetrica l shape that is probably caused by the fact that picosecond peaks in t he noise structure of the depleted pump and Stokes waves have opposite temporal profiles.