Experimental observation of stochastic resonance in a solid-state ring laser in the absence of bistability

The appearance of a stochastic resonance is found in a solid-state ring laser in the absence of bistability in it. It is shown that in this laser operating in the self-modulation regime of the first kind, the noise modulation of the pump can cause a significant increase in the laser response to the periodic modulating signal. These effects observed are explained qualitatively.