Space-charge fields in photorefractive materials enhanced by moving fringes: comparison of electron–hole transport models

Space-charge fields in photorefractive materials enhanced by moving fringes are studied for simultaneous electron–hole transport. Two distinct models, one with a single set of impurity sites and the other with two independent sets, are discussed. It is shown that the latter model gives rise to a new space-charge field resonance that depends on the relative concentration of electrons and holes. The space-charge wave concept is used in the mathematical analysis of both models.