The study on mutiphoton absorption induced photorefractive effect and fixing process

研究了多光子诱导光折变效应和光折变晶体中折射率分布的热固定过程。本文的研究成果总结如下：研究了LiNbO_3晶体的热固定工艺。它成功地连续读取全息图超过6小时，而记录的数据没有任何退化。用聚焦光束在晶体中记录的钻头数据也被固定。研究了非掺杂LiNbO_3晶体的双光子吸收过程。采用钛蓝宝石激光器作为光源。用相衬显微镜观察了诱导折射率的分布。双光子吸收过程引起的光折变效应得到了很好的验证。作为双光子工艺在光折变晶体中的应用，证明了多层光存储。介绍了七层录音和朗读，其中很少有相声。相邻位之间的距离为4 μ m，相邻层之间的距离为20 μ m。

Multiphoton induced photorefractive effect and thermal fixing process of the refractive index distribution in a photorefractive crystal had been inverstigated. The summaries in this research results are followings.1. Thermal fixing process was investigated with a LiNbO_3 crystal. It was succeeded in continuous reading the hologram more than six hours without any degradation of the recorded data.2. The bit data recorded with a focused beam in the crystal were also fixed.3. Two-photon absorption process in a non-doped LiNbO_3 crystal was inveratigated. A titanium sapphire laser was used for a light source. The induced refractive index distribution was observed wiht a phase-contrast microscope. It was very verified that photorefractive effect was induced with two-photon absorption process.4. As an application of two-photon process in a photorefractive crystal, multilayred optical memory was demonstrated. Seven layrs recording and reading with little crosstalk was presented. The distance between neighboring bits was 4 mum and neighboring layrs was 20 mum.