The Effects of Bandwidth Limiting Tuning Elements on a Synchronously Pumped Mode-Locked Dye Laser

摘要

In this study an improved description of the bandwidth limiting tuning filters has been introduced into a semiclassical model for a synchronously pumped mode-locked dye laser system. This model is an improvement over the traditional rate equation approach since it has detailed representations of the energy levels, rotational distribution, and coherence effects. The new set of equations has been solved numerically using the best available values for the various parameters, and autocorrelations have been computed for a range of different length detuning and bandwidth limiting elements. In the experiments, an acousto-optically mode-locked argon ion laser is used to synchronously pump a rhodamine 6G dye laser. To study the tuning effects, two and three plate birefringent filters and a tuning wedge have been used. Transmission and bandwidth of these filters have been carefully measured as a function of the length detuning. The autocorrelated pulses have been measured as a function of the length detuning. The experimental pulse shapes agree closely with the theoretical solutions for all values of detuning and filter bandwidth. Through a sensitivity analysis, it is shown how this model can be used to select values for the transmission and the bandwidth of the filter to obtain optimum pulse characteristics.