Laser oscillator with intracavity amplitude stabilization means

Claim 1

An optical amplifier for amplitude stabilization of laser radiation comprising: a. an active laser medium; b. excitation means optically coupled to said active medium for exciting said medium to produce a population inversion therein; c. an optical resonant cavity disposed about said active medium for stimulating the emission of radiation therefrom and for coupling a coherent output beam of radiation from said cavity; d. a non-linear absorber means for changing the frequency of radiation to a harmonic frequency comprising lithium niobate (LiNbO3) having a controllable multi-photon absorption characteristic which is at least within the spectral range of said radiation for amplitude stabilization of said radiation, placed in said resonator in series with said active medium and said resonator; e. negative feedback control means comprising: 1. means for sampling a portion of said output beam; 2. detector means for receiving said sample portion of said output beam and for generating energy proportional to the intensity of said sample portion, 3. circuit means for coupling said generated energy to said means having the controllable multi-photon absorption characteristic for increasing its absorption of said radiation as the intensity of said sampled output beam increases, and thus, for imparting a stabilizing influence on the amplitude of said output radiation.