Influence of thermally induced birefringence of an active element on the harmonic generation in a resonator under continuous pumping conditions

Thermally induced birefringence, which depolarizes the laser radiation, appears in neodymium-doped yttrium aluminum garnet elements because of the absorption of the pumping radiation. The present paper gives a theoretical analysis of the influence of this effect on the generation of the second harmonic in the resonator under steady-state and nonstationary conditions. An expression is obtained for the nonlinear coupling coefficient corresponding to "100%" conversion. The range of losses and pumping coefficients corresponding to the "100%" conversion is identified.