Abstract

A 10 kHz, broadly tunable (305-334 nm) Ce³⁺:LiLuF₄ laser is found to flip polarization when tuning about the long wavelength peak at 327 nm. We now present investigations into this behavior which show that at 327 nm the σ-polarized small signal gain is higher than π polarized small signal gain thus accounting for the polarization flipping. However it was also found that when the laser cavity forced σ-polarized laser oscillation the laser output was smaller than that obtained when π-polarized laser oscillation was forced, indicating the presence of a polarization specific loss. Absorption studies of Ce:LiLuF suggest that there is a large ESA cross-section for σ-polarization. The presence of this polarization-specific ESA would account for the reduction in power extraction efficiency for σ-polarized lasing resulting in the relatively low output powers obtained when the laser flips to σ-polarization.

© 2001 Optical Society of America