Continous-Wave two-photon transition in photoretractive crystals

光折变晶体中的连续波双光子跃迁

• 批准号: 11450026
• 负责人: TOMITA Yasuo
• 金额: $ 9.79万
• 依托单位: The University of Electro-Communications
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11450026/
• 关键词: photoretractive effect; holographic memories; two-phton transition; lithium niobate; two-photon recording; small polaron; ホログラフィック光メモリ; ニオブ酸リチウム; 小さなポーラロン

The purpose of this research is to investigate the dynamic properties of photorefractive (PR) gratings via the continuous-wave two-photon transition process in PR media and to demonstrate nonvolatile two-color holography with high figures of merit. The main results are listed below.1. We have shown that as compared with nondoped lithium niobate (LN) crystals, two-color recording sensitivity S can be increased by two order of magnitude in an Er-doped LN crystal.2. We have shown that figures of merit S and M/# can be increased up to those of near stoichiometric LN crystals when In ions are doped into congruently melted LN crystals.3. Broadband UV-induced absorption is observed in Mg-doped near stoichiometric LN crystals. It is found that the cause for such induced absorption is attributed to the formation of O^- intermediate levels resulting from photo-excited holes trapped at O^<2-> sites. We also demonstrate quasi-nonvolatile two-color holographic recording by use of this novel phenomenon.4. We demonstrate nonvolatile one-photon (near-infrared) holographic recording by use of LN codoped with In and Fe. Exchange of photo-excited electrons between bipolaron and Fe levels are considered to be a main cause for this novel phenomenon. We confirmed such a transport model by measuring near-infrared light-induced absorption changes in the UV and visible spectral regions.

本研究的目的是通过 PR 介质中的连续波双光子跃迁过程研究光折变 (PR) 光栅的动态特性，并展示具有高品质因数的非易失性双色全息术。主要结果如下： 1．我们的研究表明，与未掺杂的铌酸锂(LN)晶体相比，掺Er的LN晶体的双色记录灵敏度S可以提高两个数量级。 2．我们已经证明，当In离子掺杂到同成分熔化的LN晶体中时，品质因数S和M/#可以增加到接近化学计量的LN晶体的品质因数。 3．在掺镁的接近化学计量的 LN 晶体中观察到宽带紫外诱导吸收。发现这种诱导吸收的原因归因于由在O ^ 2- 位点捕获的光激发空穴导致的O ^ - 中间能级的形成。我们还利用这种新现象演示了准非易失性双色全息记录。4．我们通过使用掺有 In 和 Fe 的 LN 演示了非易失性单光子（近红外）全息记录。双极子和 Fe 能级之间光激发电子的交换被认为是这种新现象的主要原因。我们通过测量近红外光引起的紫外和可见光谱区域的吸收变化证实了这种传输模型。

项目成果

G. Zhang and Y. Tomita: "Broadband absorption changes and sensitization of near-infrared photorefractivity induced by ultraviolet light in LiNbO_3 : Mg"J. Appl. Phys.. (to be published). (2002)

G.Zhang和Y.Tomita：“LiNbO_3：Mg中紫外光诱导的宽带吸收变化和近红外光折变的敏化”J。

Y. Tomita and R. Kuze: "Apodization effect of a reflection photorefractive hologram with linear absorption"Opt. commun.. 183. 327-331 (2000)

Y. Tomita 和 R. Kuze：“具有线性吸收的反射光折变全息图的变迹效应”Opt。

G.Zhang, S.Sunarno, M.Hoshi, Y.Tomita, C.Yang, W.Xu: "Characterization of two-color holography performance in reduced LiNbO_3:ln"Applied Optics. 40・29. 5248-5252 (2001)

G.Zhang、S.Sunarno、M.Hoshi、Y.Tomita、C.Yang、W.Xu：“还原 LiNbO_3:ln 中的双色全息性能的表征”应用光学 40・29。 ）

G.Zhng, Y.Tomita: "Broadband absorption changes and sensitization of near-infrared photo refractivity induced by ultraviolet light in LiNbO_3: Mg"Journal of Applied Physics. 91・8(未定). (2002)

G.Zhng、Y.Tomita：“LiNbO_3: Mg 中紫外光诱导的宽带吸收变化和敏化”应用物理学杂志 91・8（待定）。

G.Zhang,Y.Tomita,W.Xu and C.Yang: "Nonvolatile two-color holography in indium-doped lithium niobate"Applied Physics Letters. 77・22. 3508-3510 (2000)

G. 张、Y. Tomita、W. Xu 和 C. Yang：“掺铟铌酸锂的非易失性双色全息术”应用物理快报 77・22 (2000)。