Characterization of structural and photoinduced defects in pure and doped lithium niobate

In this work we report on the characterization of structural and defect-related properties of a series of lithium niobate single crystals with congruent and stoichiometric composition containing Fe and Mg dopant. In particular we investigate the role of UV and visible irradiation in the charge trapping mechanisms which control the photorefractive (PR) behaviour. Complementary techniques (Raman microscopy, Electron Paramagnetic Resonance, absorption measurements) were used to characterize the degree of crystal imperfections. This is the basic starting point for an exhaustive comprehension of PR behaviour, monitored observing photovoltaic current and photoconductivity.