Polarization effects, birefringent filtering, and single-frequency operation in lasers containing a birefringent gain crystal

The effect of having a birefringent gain crystal is studied in the context of two laser systems: an intracavity frequency-doubled microchip laser and a compact single-frequency laser utilizing a birefringent filter. A model based on Jones calculus is proposed to predict the polarization and wavelength structure of the longitudinal modes and is found to be consistent with experimental measurements. The optimization of these systems is discussed, and the importance of the birefringences in the cavity and cavity length is indicated.