Investigation of the influence of a thermally induced anisotropy of an active element on diffraction losses in a single-mode laser

An approximate calculation is made of the losses experienced by the fundamental mode of a resonator containing a thermally perturbed solid active element. An analysis is made of the nature of distortions of the fundamental mode of such a resonator. It is shown that the losses depend strongly on the intermode phase mismatch, which appears during a trip through the resonator. The experimental results confirm the main conclusions reached theoretically.