Beam-mode calculations of a strongly pumped solid-state rod laser with an unstable resonator

A polarization-sensitive two-dimensional wave-optics simulation was constructed to handle the birefringence of strongly pumped solid-state rods. The simulation showed that 1.2 times diffraction-limited high-quality beams can be generated from a strongly pumped solid-state rod by use of an unstable resonator without degradation of the beam quality by the thermally induced birefringence in the rod.