Nonlinear phenomena caused by periodic electric charge distribution in piezoelectric resonator

Stong nonlinear behavior is observed in a LiNbO₃:Fe piezoelectric resonator with a photorefractive space-periodic grating. These characteristics depend on the Q-value of the resonator. The present nonlinear phenomena do not occur when the Q-value is too large, while they occur at larger values of Q in usual resonators. The mechanism of these phenomena is considered by using a one-dimensional model in which space-periodic electric charges are connected with each other. Two vibrational modes of charges, an in-phase vibration and an antiphase one, are considered in this model. Only the antiphase vibration contributes to the nonlinear phenomena. Transfer of the energy between the two modes is important for the understanding of the phenomena