  We present an obstacle in power scaling of thin-disk lasers related with
self-driven growth of misalignment due to thermal lens effects. This
self-driven growth arises from the changes of the optical phase difference at
the disk caused by the excursion of the laser eigen-mode from the optical axis.
We found a criterion based on a simplified model of this phenomenon which can
be applied to design laser resonators insensitive to this effect. Moreover, we
propose several resonator architectures which are not affected by this effect.
