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Fabrication of photonic crystals by three dimensional interference with four waves

四波三维干涉制备光子晶体

基本信息

批准号：
11650042
负责人：
SHIMURA Tsutomu
金额：
$ 2.3万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

We investigated the fabrication of the photonic crystals by three dimensional interference pattern with four lightwaves in materials whose refractive index is changed according to the light intensity. At first proposal, we tried the method using photo-sensitive polymers. Unfortunately, an British research group has reported the same results, thus, we changed the research direction slightly. We chose photorefractive materials instead of photo-sensitive polymers as a recording materials of the three dimensional interference pattern. Because the change of the refractive index is up to the order of 10^<-2>, photonic band gap cannot be realized. However, this kind of three dimensional modulation of the refractive index causes several remarkable effects, such as anomalous group velocity, and a promising candidate for the future photonic devices.When we consider the three dimensional four-wave interference, we have to take into account of the relation of the polarization of hour waves as well as the direction of k vectors. We investigated the effect of the polarization on the three dimensional interference theoretically. Also we compared the simultaneous exposure with all four waves and the sequential exposure with each set of two waves.We also studied the non-volatile recording of the three dimensional index patterns in photorefractive crystals. We tried two methods. One is a method using three levels of one element, and the other is that using two different elements as impurities. We studied two photon recording in photorefractive materials with these two methods both theoretically and experimentally. We obtained fundamental knowledge about the non-volatile recording.

研究了在折射率随光强变化的材料中，利用四种光波的三维干涉模式制备光子晶体。在最初的提议中，我们尝试了使用光敏聚合物的方法。不幸的是，一个英国研究小组已经报告了相同的结果，因此，我们稍微改变了研究方向。我们选择光折变材料代替光敏聚合物作为三维干涉图样的记录材料。由于折射率的变化高达10^<-2>数量级，光子带隙无法实现。然而，这种折射率的三维调制引起了一些显著的效应，如异常群速度，是未来光子器件的一个有希望的候选者。在考虑三维四波干涉时，必须考虑时波极化与k矢量方向的关系。从理论上研究了偏振对三维干涉的影响。我们还比较了同时曝光的所有四个波和连续曝光的每组两个波。我们还研究了光折变晶体中三维折射率图的非易失性记录。我们尝试了两种方法。一种方法是使用一种元素的三个层次，另一种方法是使用两种不同的元素作为杂质。从理论上和实验上研究了这两种方法在光折变材料中的双光子记录。我们获得了关于非易失性记录的基本知识。