APERTURE GUIDING IN QUASI-3-LEVEL LASERS

Aperture guiding, as opposed to thermal waveguiding, is shown to be th e dominant mechanism for cavity mode stabilization in a quasi-three-le vel Yb:YAG laser in a flat-flat resonator. Excellent agreement is obta ined between the experimental and modeled spot sizes in this laser whe n aperture guiding is included in the model. The models show that the spot size is insensitive to the exact form of the dependence of the tr ansmission of the aperture on the transverse dimension. This finding i s expected to affect other quasi-three-level lasers.