The present embodiment provides a system and method for lowering the saturated gain level of a thin-disk laser oscillator by multipassing each gain generator in such a way to cancel some of the wavefront error contributions from the disk surfaces. Wavefront aberrations introduced on one pass of the gain disk are canceled through symmetry on successive passes. The reduced wavefront error significantly improves design space for single-mode resonators. Maximum effectiveness is achieved by rotating the gain disk so that the fold plane-of-symmetry reverses the largest wavefront error or specifically chosen functional forms.