利用週期性金屬貼片陣列操控表面等離子極化激元與倫伯格透鏡之設計

Abstract

本論文探討應用週期性結構於倫柏格透鏡，我們使用的週期性金屬貼片陣列是一種表面超材料，可以用來合成倫伯格透鏡，使在其表面傳導的表面等離子極化激元達到應有功能表現。 首先本論文提出應用表面阻抗的方法，找出各級金屬貼片的表面阻抗並提供公式將其轉換成為透鏡的重要參數-折射率。有了此參數之後就能將倫伯格透鏡的折射率分布離散化，並使用金屬貼片近似之，已達成預期的透鏡表現。 本論文提出好幾種由不同大小的金屬貼片陣列所合成的倫伯格透鏡，並比較、精化他們的透鏡表現以及提供他們的設計原理及細節。最重要的一點是，本論文建立了離散的週期性結構與連續的倫伯格透鏡之間的連結。

The thesis presents a surface constituting arrays of periodic patches, which may serve as the metasurface to synthesize the Luneburg lens. The main purpose is by using different sizes of patches to achieve different refractive index at each stage, and get the proper function of Luneburg lens. We propose several plasmonic lens in this thesis showing their design philosophy, details, and try to refine the performance of these lens. We also put them together and make comparisons. We deliver a method to build a well-functioned Luneburg lens step by step in the context. Starting with defining surface impedance and giving formulas to turn it into a refractive index for synthesizing Luneburg lens. Most importantly, we make a linkage between periodic structures and Luneburg lens in the work.