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Nonliner optical effects in the quasi one-dimensionally ordered dielectric microspheres

准一维有序介电微球的非线性光学效应

基本信息

批准号：
12450033
负责人：
HARAGUCHI Masanobu
金额：
$ 6.14万
依托单位：
The University of Tokushima
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

1) We have established the technique for fabrication of the one-dimensionally ordered dielectric micro-spheres, whose diameter is several μm, by micromanipulator and self-organization of spheres on the glass substrate formed the groove with several μm depth by the lithography technology. Optical characteristics of a single and/or the ordered spheres using attenuation total reflection (ATR) configuration, I.e., evanescent coupling, have been able to measure with optical fiber probes which sharpened by the etching.2) We have fabricated several types of nonlinear optical microspheres coated a nonlinear thin film on a silica sphere whose diameter is about 10 μm : typically the sol-gel method for a titania glass film dispersed gold nanoparticles and the deposition method in vacuum for phthalocyanine or isoviolanthrone thin films. The microsphere coated a nonlinear film with several hundred nm thickness have shown the nonlinear optical responses in the ATR configuration with the short-pulsed laser.3) Using the finite-difference time-domain (FDTD) method, we have shown numerically that the substrate gives large effects in resonance mode excited by the evanescent coupling because the energy of the mode can escape easily to the substrate. Moreover, FDTD method including the Kerr effect has been developed. Using this, we have numerically revealed that the 1 μm diameter sphere fabricated by a semiconductor can show the optical switching characteristic in the ATR configuration.4) As a first step for the development for the FDTD including the time delay of the nonlinearity, FDTD program including the Drude dispersion of linear dielectric constant of a metal particle has been developed to simulate the linear optical response on metal nano-particle. Using this, the resonance response related to the localized polariton in metal nano-particles can be evaluated numerically.

1)我们建立了利用微操作器和微球自组织技术在玻璃基片上制备直径为几μm的一维有序介质微球的技术，并利用光刻技术在玻璃基片上形成了几μm深的沟槽。使用衰减全反射（ATR）配置的单个和/或有序球体的光学特性，即，2）在直径约为10 μm的石英球上制备了几种非线性光学微球：溶胶-凝胶法制备了分散有金纳米粒子的二氧化钛玻璃膜，真空沉积法制备了酞菁或异蒽酮紫薄膜。在短脉冲激光作用下，微球表面覆盖一层几百nm厚的非线性薄膜，在ATR结构中表现出了非线性光学响应。3）利用时域有限差分（FDTD）方法，数值计算表明，在倏逝波耦合激发的谐振模中，由于模的能量很容易逃逸到衬底中，所以衬底对谐振模有很大的影响。此外，FDTD方法，包括克尔效应已经发展。数值模拟结果表明，用半导体材料制作的直径为1 μm的球在ATR构型下可以显示出光开关特性。4）作为发展包含非线性时延的FDTD的第一步，开发了包含金属颗粒线性介电常数Drude色散的FDTD程序，模拟了金属纳米颗粒的线性光学响应。利用此方法，可以数值计算金属纳米粒子中与局域极化激元相关的共振响应。