Enhancement of blue holographic properties in Zr~(4+)-doped near stoichiometric Fe:LiNbO_3 crystals

摘要

The near stoichiometric LiNbO_3 crystals co-doped with ZrO_2 and Fe_2O_3 have been grown from a Li-rich melt (Li/Nb=1.38, atomic ratio) by the Czochralski method in air atmosphere at the first time. The OH~? absorption and UV-vis absorption spectra were characterized to investigate the defect structure of the crystals. The appearances of the 3479 cm~(?1) absorption peak and 358 nm absorption edge manifest that the composition of the grown crystal is close to the stoichiometric ratio. The blue holographic properties were also measured by the two-wave coupling experiments. As a result, in the near stoichiometric Zr:Fe:LiNbO_3 crystals, photorefractive response speed, recording sensitivity, and two-wave coupling gain coefficient are significantly enhanced. Meanwhile, the high saturation diffraction efficiency is still maintained. These findings prove that the material of near stoichiometric Zr:Fe:LiNbO_3 crystals are a promising candidate for blue photorefractive holographic recording.