THEORETICAL AND EXPERIMENTAL STUDIES OF SLAB GEOMETRY LASERS

There is a recognized need for high power tunable sources in the infrared. Such sources have applications in spectroscopy, laser induced chemistry and in remote sensing of airborne contaminants in both the atmosphere and in laboratory experiments. Solid state Nd:Glass lasers in combination with stimulated Raman scattering is an attractive method for filling this need. The problem with present Nd:glass lasers is that they are limited to low average power outputs by thermally induced birefringence and stress induced biaxial focusing. The use of a zig-zag optical path slab geometry host offers a method of extending these limits and thus increasing the average power achievable with Nd:Glass lasers. Furthermore, this technique has applications to increasing the average power achievable with other solid state laser materials.;A test bed slab laser has been designed and built. The performance of this slab laser is compared with the predictions of the computer model. It is shown that the slab geometry does increase the average power achievable in Nd:Glass lasers, and that the computer model is a useful tool in predicting the performance of these lasers.;The theory necessary to analyze thermally induced optical effects in isotropic materials is presented. This theory is used to analyze the thermal effects in both a rod and an idealized infinite slab. The basic overview of a computer model for a zig-zag optical path slab laser based on the theory is developed, and verification methods are presented. A theory of second order effects is also developed, and it is shown that these effects should not be a problem in zig-zag optical path slab geometry lasers.