OPTICAL LIMITER INCLUDING OPTICAL CONVERGENCE AND ABSORBING BODY WITH INHOMOGENEOUS DISTRIBUTION OF REVERSE SATURABLE MATERIAL

摘要

A lens (12) converges a light beam (16) into a light absorbing body (14) having a material which exhibits reverse saturable optical absorption distributed therein with a non-uniform concentration. The concentration is maximum at the focal point (20) of the converged light beam (16), and decreases toward the lens (12) with a distribution selected in correspondence with the optical gain of the converged light beam (16) to limit the local fluence of the light beam (16) propagating through the absorbing body (14), and the output energy of the light beam (16), to predetermined maximum values. The non-uniform concentration further produces a self-protecting effect by causing the region of maximum fluence of the converged light beam (16) to shift toward the lens (12), thereby protecting the region of highest optical gain and highest molecular concentration, as the input energy of the light beam (16) increases.