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

1)建立了利用微机械臂制备直径为几μm的一维有序介质微球的工艺，并利用光刻技术在玻璃基板上自组织形成几μm深的凹槽。利用衰减全反射（ATR）结构，即倏逝耦合，可以测量单个和/或有序球体的光学特性。2)在直径约为10 μm的二氧化硅球上制备了几种非线性光学微球，其中典型的是溶胶-凝胶法制备二氧化钛玻璃膜分散金纳米粒子，真空沉积法制备酞菁或异紫王座薄膜。微球包覆了一层厚度为几百nm的非线性薄膜，在短脉冲激光作用下显示出ATR构型下的非线性光学响应。3)利用时域有限差分（FDTD）方法，我们在数值上证明了基片对倏逝耦合激发的共振模式的影响很大，因为模式的能量很容易逃逸到基片上。此外，还提出了考虑克尔效应的时域有限差分法。利用这一方法，我们通过数值计算揭示了由半导体制成的直径为1 μm的球体在ATR结构下可以表现出光开关特性。4)为了模拟金属纳米粒子的线性光学响应，开发了包含金属粒子线性介电常数德鲁德色散的FDTD程序，作为开发包含非线性时间延迟的FDTD的第一步。利用这种方法，可以对金属纳米粒子中局域极化子的共振响应进行数值计算。

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.