[en] This project has focused on a number of related topics in nonlinear optics, unified by the theme of temporal fluctuations in the light field emitted by broad-band lasers. The following new results were obtained: the shot-to-shot statistics of multimode, pulsed dye lasers were measured, and cross correlations between mode energies were observed and explained; evidence for phase locking between the modes was also obtained; a new technique was demonstrated for smoothing the intensity fluctuations of the pulses emitted by multimode dye lasers; the influences of laser bandwidth in the stimulated Raman scattering process were studied experimentally and theoretically; a theoretical study was carried out to predict the effects of laser bandwidth in the spectrum of light scattered by atomic vapors; and fluctuation dynamics and instability behavior of multimode continuous-wave dye lasers were studied experimentally and theoretically. The mechanism for mode intensity fluctuations was found to be four-wave mixing, which is a deterministic process, not noise driven. 9 refs