The photorefractive characteristics of bismuth-oxide doped lithium niobate crystals

Bismuth-doped lithium niobate (LN:Bi) crystals were grown by Czochralski method and their optical damage resistance, photorefraction, absorption spectra, and defect energy levels were investigated. The experimental results indicate that the photorefractive properties of LN: Bi were enhanced as compared with congruent one, the photorefractive response time was greatly shortened, the photorefractive sensitivity was increased, and the diffraction efficiency of near-stoichiometric LN: Bi (SLN:Bi) reached 31.72% and 49.08% at 532 nm and 488 nm laser, respectively (light intensity of 400mW/cm(2)). An absorption peak at about 350 nm was observed in the absorption spectrum of LN: Bi. And the defect energy levels simulation indicates new defect levels appear in the forbidden gap of LN: Bi crystals. Therefore bismuth can act as photorefractive centers in LN crystals. (C) 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.