Magnetophotorefractive effect in LiNbO₃:Fe crystals: theory and experiments

A theoretical and experimental analysis of the magnetophotorefractive effect for a vectorial holographic recording scheme is presented. Analytical expressions for the magnetic-field effect on space-charge field formation, two-wave coupling, and grating diffraction efficiency are given. A new, photovoltaic magnetic coupling vector that describes the magnetic-field dependence on grating formation is introduced. Good agreement with the theoretical predictions is found for new experimental results in the short time limit. These results show, for the first time to our knowledge, an enhancement of 60% of the diffraction efficiency caused by external application of a magnetic field with a magnitude of 0.2 T. The method provides a new all-optical technique for investigating the magnetophotovoltaic effect. Components of the magnetophotovoltaic tensor for crystals of LiNbO₃:Fe are determined experimentally.