Magnetophotorefractive effect and interference filters in lithium niobate

This thesis deals with the fundamental photorefractive and photovoltaic properties of iron-doped lithium niobate crystals. Experimental observations of a strong magnetic field effect on the energy coupling and grating formation in a vectorial interaction scheme are presented. To the author's knowledge these are the first reported results in the field. It is shown that an enhancement of the diffraction efficiency of 60% is possible by applying even a moderate magnetic field of 0.23 T. A new theoretical model of the magnetophotorefractive effect in the vectorial interaction scheme is presented. It describes the space-charge field formation, two-wave mixing and grating formation under the influence of an externally applied magnetic field. Good agreement with the experimental results and the first measurement of nondiagonal components of the magnetophotovoltaic tensor are reported. A theoretical model for the temperature properties of photorefractive interference filters with subangstrom bandwidths are presented and compared favourably with experimental investigations. A novel method for determining the spectral response of these filters from a combined thermal and angular response measurements is described. (au) 9 tabs., 30 ills., 84 refs