Analysis of Plasmonic Waveguides with Right-Angled Corners and Edges Using a Full-Vectorial Imaginary- Distance Finite-Element Beam Propagation Method

• Main Authors: Jia-jheng Lin, 林家正
• Other Authors: 張宏鈞
• Format: Others
• Language: en_US
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/87086963460448748081

碩士 === 國立臺灣大學 === 電信工程學研究所 === 97 === In this thesis, we adopt the full-vectorial finite element imaginary-distance beam propagation method (FE-ID-BPM) based on the hybrid edge/nodal elements and the incorporated perfectly matched layers (PMLs) to analyze several plasmonic waveguides. We start from the simplest, infinite 3-D plamonic waveguide, which is uniform in propagating direction, for investigating the basic characteristics. Then based on those concepts, we introduce some waveguides, such as edge and stripe plasmonic waveguides. We investigate how the size of the edge will affect the confinement and attenuation of surface plasmon polariton (SPP) edge mode. We show three types of SPP modes, including leaky, bound, and edge modes, supported by the stripe waveguide. The limited width of a thin stripe, which can support the bound mode, is analyzed by some approximation, and the results agree with that calculated by the FE-ID-BPM numerical model. Comparison among the modes is discussed. Then, we look into the coupling phenomenon of two single elements. The coupling in- duces symmetry and antisymmetry modes, which can both be numerically obtained using the FE-ID-BPM. Related plasmonic slot and stripe waveguides are studied, and their mode patterns and dispersion diagrams presented. We calculate the effective propagating constant and attenuation for different spacings of the two adjacent stripes. The crosstalk between the coupled stripes is then evaluated.