Sub-10-fs operation of Kerr-lens mode-locked lasers

We present results of a three-dimensional model of a Kerr-lens mode-locked titanium-doped sapphire laser in the sub-10-fs regime of operation. We find that space-time focusing of the pulse within the laser crystal imposes a limitation on the pulse duration as a function of the crystal length. Thus good compensation of the net group-velocity dispersion of the cavity is not sufficient for successful sub-10-fs operation of the laser. The dependence of the pulse duration on the intracavity dispersion is also presented, which demonstrates that pulses as short as 6 fs can be generated directly from the laser. (C) 1996 Optical Society of America