Solid-state ring laser with an external signal

An analysis is made of the operation of a solid-state ring laser in the presence of a weak external signal. A transient solution is obtained in the instability range in the absence of such a signal. Then, consideration is given to the influence of a unidirectional external signal, an external signal in combination with nonresonant backward stimulated scattering, and two independent contrarotating signals. Widths of the frequency-locking regions and the criterion of amplitude stabilization are found and the conditions for the existence of the traveling-wave regime and of the maximum transfer of energy to the scattered radiation are established. The results are given of experiments carried out using a ruby ring laser in the presence of a unidirectional external signal. A qualitative agreement between the theoretical conclusions and the experimental results is reported.