Abstract

We report new experimental results on a coupled cavity moving mirror ring dye laser operating with a repetition rate of 250 MHz. Existing published models for the mode-locking mechanism are analyzed in light of the various experiments performed in this study. We find thresholds for the onset and instability of kinematic mode locking (KML) as a function of pump power. The pulse length dependence on mirror velocity and cavity detuning are found as well as mirror velocity asymmetries. We show that the multimode noise manifested in the width of the cavity beat note at 250 MHz appears to be but is, in fact, not correlated with the required mirror velocities for mode locking, as previous models have conjectured. A prism pair is added to the external cavity for group velocity dispersion compensation, which with proper adjustments can also tune the laser over the entire rhodamine 6G bandwidth. With the inclusions of prisms, the mode locking is found to be more stable and pulses shorter than 3 ps are obtained.

© 1992 Optical Society of America