Metallic waveguide cavity with a spherical mirror

The influence of the curvature of the spherical mirror for metallic waveguide resonator of submillimeter laser (λ = 0.4326 mm) on energy losses and the mode composition of radiation is investigated. It is shown that the presence of quadratic phase aberrations in the mirrors of the waveguide cavity with an increase of its Fresnel number at monotonically decreasing of the energy losses for fundamental asymmetric mode TE
_11q
due to a decrease of waveguide losses also leads to their substantial non-periodic oscillation.