EXTERNAL SEEDING OF STIMULATED RAMAN-SCATTERING IN MICRODROPLETS

External seeding of stimulated Raman scattering (SRS) in microdroplets is achieved by light injection into the droplet at the Raman-shifted frequency. Two implementations permit observation of the seeding effec t. First, a broadband seed laser (similar to 2 nm FWHM) is used to spe ctrally discriminate the elastically scattered seed light from the nar row-linewidth SRS. Second, a crossed analyzer is used to reduce by sev eral orders of magnitude the intensity of the detected elastically sca ttered seed laser, preventing saturation of the detector. Seeding of S RS in microdroplets is effective in enhancing the signal from weak-gai n Raman modes but does not significantly increase the SRS intensity fr om strong-gain Raman modes. (C) 1996 Optical Society of America