Self-focusing phenomena in air-glass laser structures

The effect of the air space on self-focusing instability growth rates has been considered for glass laser systems. The situation may be viewed as a min-max problem in which the air space may be adjusted to minimize the fastest growing instability. A solution exists to the min-max problem which reduces the problem to the solution of a single transcendental equation. Solutions to this equation indicate that, at most, a 10-percent reduction in the effective value of the non-linear index of refraction can occur.