於具有多層金屬結構及一維金屬光柵結構內 表面電漿子特性研究

Abstract

本論文的重點在於以研究表面電漿波在多層金屬以及在次波長金屬光柵之光學特性為基礎，來展現各種與表面電漿激發有關之現象，如表面電漿之色散曲線及高穿透效率。首先以分析表面電漿在多層金屬結構下之解析解，來探討在多層不同金屬的結構下，不同金屬厚度改變時以及不同組合狀況之下，其表面電漿之色散曲線之擾動及場分布變化的情形。之後，我們藉由頻域有限差分法來分析在結構金屬具有次波長金屬光柵情況下，及在光頻範圍內，穿透效率對其頻率隨著不同結構參數的變化而有所改變，以及在結構附近之近場場型分佈的情況，來討論表面電漿對其高穿透特性的影響。此外，比較以不同金屬組合成金屬光柵與單金屬組成之金屬光柵情況下，其穿透效率特性的不同之處。

A surface plasmon polariton (SPP) is an excitation on the boundary of a metal whose oscillations of surface charges produced by exterior electromagnetic waves. The aim of this thesis is to discuss the properties of SPs in the multi-layer structures and in metallic gratings. First, through Davidenko’s method to find the analytical solutions of the multi-layer structures, the dispersion relation of the SPs and its modal fields can be plotted for us to know the subtle variations of SPs by varying the thickness of metals. Then, since the activities of SP are so sensitive to metallic structures, we introduce the finite-difference frequency-domain method to study the interactions between SP and shaped structures. By analysis of the transmission and field distributions, we show how the SP to affect the transmission spectra with different parameters of one-dimensional metallic gratings. Besides, we also calculate the cases of one-dimensional metallic gratings consisting of two kinds of metals to compare with that of only one kind of metal.