Wide hysteresis regions experimentally observed in the lock-in range in a Zeeman ring laser have not been described theoretically until recently. In the present article, a new model that accounts for the absorption of laser radiation in the resonator mirrors is proposed. Expressions are derived for the coupling coefficients of counterpropagating waves due to their diffraction on absorption gratings. Experimental studies of the hysteresis of the lock-in range in a Zeeman RL have been carried out. Numerical simulations based on the proposed model yield results that are in qualitative agreement with the experiment.
Grushin et al. (Mon,) studied this question.