Dynamics of emission from dye lasers pumped synchronously by finite picosecond pulse trains

A theoretical model is developed of generation of ultrashort light pulses in synchronously pumped dye lasers. Representation of the active medium by a four-level system makes it possible to study in detail the kinetics of establishment of synchronous operation and to calculate the ultimate parameters of such lasers. Special attention is given to the transient operation of synchronously pumped dye lasers and to transient processes in generators of high-power ultrashort pulses excited by relatively short trains from picosecond solid-state lasers. The theoretical model is shown to agree well with the experimental results. Calculations based on this model were used to construct a stable generator of spectrally limited frequency-tunable pulses of 8 psec duration by excitation with a train of second-harmonic pulses from a picosecond neodymium glass laser.