Mode locking with a compensated space–time astigmatism

We present what is to our knowledge the first full spatial plus temporal model of a self-mode-locked titaniumdoped sapphire laser. The self-consistent evolution of the pulse toward steady state imposes strong space-time focusing in the crystal, where both the space and time foci are located. This combined focusing significantly improves the discrimination properties of the nonlinear resonator for shorter pulses and reduces the transient stage of pulse formation. Our theoretical results are in very good agreement with experiment.