Operation of a femtosecond Ti:sapphire solitary laser in the vicinity of zero group-delay dispersion.

We report the operating characteristics of a self-mode-locked Ti:sapphire solitary laser at reduced group-delay dispersion. The generation of asymptotically equal to 12.3 fs near-sech(2) optical pulses at 775 nm is reported, together with experimental evidence for the dominant role of third-order dispersion (TOD) as a limiting factor to further pulse shortening in the oscillator. At reduced second-order dispersion excessive residual TOD is shown to lead to dispersive wave generation, and the position of the dispersive resonance is used to determine the ratio of the net second- and third-order intracavity dispersions. Since the magnitude of TOD rapidly decreases with increasing wavelength in prism-pair dispersion-compensated resonators, the oscillator presented has the potential for producing sub-10-fs pulses in the 800-nm wavelength region.