The gain and propagation constants, characterizing a lenslike medium, are calculated on the basis of some experimental results on the parameters which determine the Gaussian beam in its fundamental mode. The experiments were carried out with a ruby and a glass neodymium laser. The amplification and refraction effects are more important in the ruby as they are in the neodymium case. If the length of the optical cavity s large with respect to the length of the rod amplifier, an apparent change is observed in the characteristic parameters of the lenslike medium.

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The intensity distribution of the nonlocalized rings from a Fabry-Perot standard is calculated. This is illuminated by a point source in order to characterize the interference pattern. The results show that the rings are identical with the nonlocalized rings around the principal (Gaussian) beam from a solid state laser (ruby or neodymium). A synthesis of the results obtained by different authors is presented, and we show that the rings arise from energy losses caused by diffusion or reflection of the Gaussian beam in the laser cavity.

The influence of quadratic pump power distribution on transverse spatial hole burning in homogeneously broadened lasers is analyzed. The optimum relationship between pump size and mode size is given. Theoretical and experimental results are compared for neodymium lasers with helical xenon lamp pumping. From the excellent agreement between theory and experiment we can conclude that the pump intensity radial distribution near axis is close to the quadratic law. The experimental quadratic term is measured. Laser performance as a function of the optical cavity parameters is analyzed.