Mode structure in an anisotropic resonator consisting of two corner-cube prisms

Analytic and numerical investigations are reported of the mode structure in an anisotropic resonator composed of two corner-cube total-internal-reflection prisms. It is shown that polarization aberrations transform significantly the mode structure and increase the diffraction losses. In the range of moderately high Fresnel numbers the lowest resonator modes form a group which is quasidegenerate in respect of the losses. The eigenstates of the modes are spatially inhomogeneous and differ from those predicted by geometric optics.