Stabilization of ruby laser radiation by an external negative feedback

The intensity and emission spectrum of a ruby laser, stabilized by an external negative feedback, were determined. An experimental study was made of the influence of the delay time and strength of feedback on the stabilization of the radiation intensity. The effects of perturbations of the Q factor of the resonator on the stabilization were investigated. It was found that the sensitivity of the laser to perturbations did not exhibit resonance at some perturbation frequency.