Multiple scattering of optical pulses in scale model clouds

Results are presented of experiments designed to measure the delay, temporal stretching, attenuation, and spatial spreading of optical pulses in scale model clouds. The model cloud systems employed either diiodomethane/water or paraffin oil/water emulsions maintained in a rotating scattering cell in order to prevent the settling of the droplets. A frequency-doubled passively mode-locked Nd:YAG laser was employed to generate 532 nm, 25 ps duration optical pulses, which were detected with a 10 ps resolution streak camera. Direct measurements of the delay in the mean arrival time of the pulses due to multiple scattering are presented.