以全向量虛軸有限元素波束傳播法分析脊形、槽形 與V形表面電漿子波導

Abstract

此篇論文利用全向量虛軸有限元素波束傳播法分析研究表面電漿子波導，討論的結構包括脊形波導、槽形波導及V形波導。針對不同的結構參數我們計算波導之有效折射率、傳播長度、模態場型以及色散關係。對於具有一薄層低介電質材料介於金屬和高介電質材料之間的脊形波導，討論不同薄層厚度對於傳播模態的影響。對於槽形波導中，討論在槽中間填充不同分佈的高介電質材質時，對於模場的侷限性和傳播長度的影響以及在不同寬度或厚度的高介電質材質對於減少損耗的可能性。對於具有有限高度和厚度的金屬之V形波導，討論不同金屬層厚度對於通道電漿子模態和楔形電漿子模態特性的改善。

This research studies the surface plasmon polariton (SPP) waveguides using the finite element imaginary-distance beam propagation method (FE-ID-BPM). The rib waveguide, slot waveguides, channel plasmon, and V-shaped waveguides are investigated. The effective indices, propagation lengths, modal field profiles, and dispersion relations are calculated for various structure papramters. In the rib waveguide with a layer of low-index material located between the metal cap and the high-index material layer, various layer thicknesses are examined to understand different guided- mode characteristics. In the slot waveguide, a high-index material is introduced in the slot and mode field confinement and propagation length analyzed for different widths and heights of the high-index material for possible loss reduction. In the V-shaped waveguide with a metal layer of finite thickness, the characteristics of the channel plasmon polariton (CPP) and wedge plasmon polariton (WPP) modes for different metal-layer thicknesses are studied.