Abstract

A short-cavity dye laser has been constructed to study fluctuations arising from quantum noise and mode coupling in multimode systems. Typical dye lasers (i.e., long-cavity) have been found to have cw dynamics that are dominated by coherent wave mixing effects.¹ The quantum noise in these lasers also manifests itself as a variance in the buildup times of the laser light intensity. Buildup times of singlemode long-cavity lasers have been studied.² The relative importance of quantum noise is enhanced in short cavities making the turn-on transient the dominant feature in the laser light fluctuations. We have measured the turn-on transient of individual modes from a multimode short-cavity dye laser following sudden turn-on of the pump power. The shortness of the cavity has the effect of making the decay times of the intracavity field and the molecular population similar. The observed buildup and rise times are compared with those predicted by a semiclassical multimode laser theory with stochastic noise added for several pump rates. Moreover, semiregular oscillations of the total intensity have been observed to occur in short bursts separating intervals of nearly constant cw laser output.

© 1991 Optical Society of America