Research On Light-induced Absorption Of Lithium Niobate

Lithium niobate is one of the most important crystalline materials for nonlinear optical application of all kinds. It is utilized in lasers, electro-optic, acousto-optic, and optical storage devices. Precise knowledge of the light-induced charge transport governed by defect centers of LN is an indispensable prerequisite for any of these applications. Light-induced absorption experiment has been used to study the electronic transfer mechanism of electro-optical crystal (such as LiNbO3, KNbO3, and BaTiO3). The light-induced absorption knowledge, on the one hand, can provide an insight into the mechanism of the light-induced charge transport process. On the other hand, it can offer considerable guidance to record a desired hologram for the application in formation storage or integrated optics.Now research on the light-induced absorption of the lithium niobate almost focus on reduced, doped lithium niobate, and the growth state of near-stoichiometric crystal and stoi-chiometric crystals lack of concern, the basis of the corresponding carrier mobility model has not yet established. The Polaron of Lithium niobate plays an important role in the carrier transport processes, which is as the donor or acceptor of electron in the crystal. Study about polaron is almost aimed at bipolaron and bound small polaron, at the same time the reports about hole polaron, free small polaron, and Q-polaron is few.Based on the above viewpoints, The main work in this paper includes:1,Completely summarizes the factors which influence the concentration of bipolaron, small polarons, and free small polaron as well as the relation between the concentration of polarons and the light-induced absorption;2,Study on light-induced absorption of lithium niobate crystals with different com-ponents, and analysis the results.Theoretical analysis and experimental results indicate that the discussion about the charge transfer mechanism of lithium niobate after pulsed illumination should includes O-hole polaron. The mechanisms are dicussed on different proposed band scheme in this paper.