标题: | 二维光子晶体特性探讨与光学元件之设计 Researches on Characteristics of Two-Dimensional Photonic Crystals and Designs of Optical Devices |
作者: | 裴廷汉 Ting-Hang Pei 黄远东 Yang-Tung Huang 电子研究所 |
关键字: | 光子晶体;等效折射系数;散射;Y型波导;超錂镜效应;超导体;photonic crystal;effective refractive index;scattering;Y-branch waveguide;superprism effect;superconductor |
公开日期: | 2007 |
摘要: | 本论文提出二维光子晶体的等效折射系数(Effective refractive index)之旋转不变性以及光在具有缺陷(Defects)中的散射现象之探讨。光子晶体对于光由空气入射,于某些特殊的等频率面(equal-frequency surface),其等效折射系数具有旋转不变性。此外,由于光子晶体于某些频段中,其光学性质可以由各方向均一的等效折射系数来表示,因此于这些频段中,可以由等效介质来讨论缺陷的散射问题,并进一歨可设计出具周期性缺陷的光子晶体,其特别处可将原本不具光子晶体能隙(Photonic band gap)处,产生新的光子晶体能隙。 应用光子晶体设计的光学元件,则包括设计异质结构光子晶体Y型分歧波导(Heterostructure photonic crystal Y-branch waveguide),以及利用超导体光子晶体的温度变化而设计的马赫任德干涉仪(Mach-Zehnder interferometer)。设计的异质结构光子晶体Y型分歧波导,可以增加波导的宽度,以利与其他光学元件如光纤的耦合,并可达到高传输效率。超导体光子晶体对温度的敏感特性,可有效地改变入射光方向。利用超导体的温度变化,可以设计具有开-关性质的光学元件。 This thesis discusses the invariance of the effective refractive index of the two-dimensional photonic crystal under the rotation operator on the equifrequency surface and the scattering phenomena by defects. The effective refractive index can be defined when light is incident from the free space into the photonic crystal. We find out only two solutions of the equifrequency surface possess invariant effective refractive index when the equifrequency surface is rotated by a symmetry operation. Besides, the photonic crystal can be represented homogeneously by the effective refractive index within a certain frequency band, the scattering phenomenon scattered by defects can be discussed by the effective medium with effective defects. Finally, a periodic-defects photonic crystal is proposed. Some photonic-crystal optical devices are designed, including the photonic crystal heterostructure Y-branch waveguide and the temperature modulation photonic crystal Mach-Zehnder interferometer composed of copper oxide high-temperature superconductor. The photonic crystal heterostructure Y-branch waveguide has a large width of the waveguide, which is benefit to couple to other optical device, such as the fiber, and reaches a high-efficiency transmission. The sensitive characteristics of the superconductor photonic crystal can change the propagation direction of light efficiently. The on-off optical device can be designed by using the temperature variation of the superconductor. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#GT008811824 http://hdl.handle.net/11536/54445 |
显示于类别: | Thesis |