Compensation of birefringence induced in laser systems by passive anisotropic elements

An analysis is made of two systems for compensating birefringence induced in an active element when thermal stresses in the element have a longitudinal symmetry plane. Simple passive anisotropic elements are used in both systems. The Jones matrix method is used to demonstrate that these systems, together with thermally stressed active elements, are equivalent to a half-wave phase plate. An estimate is obtained of the influence of a thermal lens formed in an active element on the birefringence compensation process. Experiments proving the feasibility of the systems are reported. A periodic double-pass amplifier based on these systems is proposed.