Third-order dispersion in a passively mode-locked continuous-wave dye laser

摘要

The pulse duration tp of a colliding-pulse mode-locked dye laser is measured versus the intracavity third-order dispersion (TOD), where the group-velocity dispersion is optimized by a four-prism sequence. The intracavity TOD is varied by the addition of layers on quarter-wave dielectric-multilayer mirrors. The shortest pulse is observed at a nonzero TOD. The TOD dependence of tp is explained by a new model that describes the saturation of absorption and gain dyes in the frequency domain, with the assumption of a steady sech2-shaped pulse with weak chirp and a negligible fast self-phase modulation.