利用時域有限差分法與耦合波分析法於表面電漿元件之分析研究

Abstract

本論文以研究穿透式與反射式次波長金屬光柵之光學特性為基礎，利用模擬方式展示各種表面電漿波的現象，其中包括表面電漿輔助高穿透現象，表面電漿色散曲線之擾動，以及近場能量提高自激放光特性。藉由金屬光柵之設計，我們可以改變表面電漿波的特性，例如色散曲線。故此，我們採用耦合波法與時域有限差分法系統化的探討表面電漿波與結構間的關係特性。其中以耦合波法計算表面電漿色散曲線與此金屬光柵的繞射效率，並利用時域有限差分法模擬表面電漿波在近場的分布情形。此外，兩數值方法所得結果亦可相互驗證，確定此模擬之可靠度。歸納模擬之結果與經驗，我們進一步提出利用表面電漿波與異常穿透之特性的新型顯示架構，此外我們也針對表面電漿提高近場強度之特性研究原子自激放光與金屬結構的關係。

A surface plasmon polariton (SPP) is an electromagnetic excitation existing on the metal surface. The electromagnetic behavior and interactions with metallic structures make surface plasmon (SP) possess various unusual properties. The aim of this thesis is to investigate the physical properties of extraordinary transmission, which is one the unusual properties of SP. In addition, we focus on the near field enhancement induced by SP resonance. Since the activities of SP are so sensitive to metallic structures, we introduce the finite-difference time domain and coupled-wave methods to corporately study the interactions between SP and shaped structures. At first, we examine the SP-assisted transmission and the field distributions near metal surface. Based on this analysis, we proposed a liquid crystal based plasmonic display device and further discuss its operating properties. In the following sections, we study the strong field enhancement and localization of SP and further utilize semiclassical approach to study the spontaneous emission (SE) of an atom in the presence of metallic gratings. Through various numerical studies, we also reveal some physical essence of SE behavior when an atom resonantly couples to SP modes.