以電磁理論模擬探討與尋找新奇負折射超穎材料

Search for novel negative refraction index metamaterials by electromagnetic simulations

詹勳奇(Hsun-Chi Chan)

指導教授 ： 郭光宇

國立臺灣大學/理學院/物理研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.00782

摘要

我們提出一種新的負折射超穎材料(Negative index metamaterial)，其單元是由一對站立 U 形環所組成的人工原子(meta-atom)，並用有限元素法(Finite element method)對此系統進行數值模擬與分析。此種超穎材料的等效介電常數(effective permittivity)與導磁係數(effective permeability)在近紅外波長區間內[1080nm~1260nm]同時為負值，因此在相當寬的頻寬內(180nm)具有等效的負折射率(n~-2)。此外，我們還優化系統的幾何參數，使得系統的等效阻抗與外界空氣匹配(impedance matching , z~1)，並且系統的品質因子(figure of merit)在1200nm左右達到最高值(FOM=20.6)。最後，我們用這個超穎材料做了一個單層平板和一個楔形稜鏡，並對這兩個系統
做了數值模擬(numerical simulations)，証明這種超穎材料的確具有負折射現象。

關鍵字

雙負超穎材料 ； 裂環共振器 ； 古典電磁理論 ； 數值模擬

並列摘要

Negative index metamaterial composed of the upright split-ring pair as one meta-atom has been investigated numerically by finite element method. This new metamaterial
possesses both negative effective permittivity and negative effective permeability overlapping in the near-infrared region [1080nm~1260nm], hence exhibiting a negative
index of refraction (n~-2) with a broad double negative bandwidth (180nm). We also tune the geometric structure parameters to optimize the metamaterial, thus achieving a
good impedance matching (z~1) and a rather high figure of merit (FOM=20.6) at the wavelength around 1200nm. Finally, numerical simulations demonstrate that both
single-layer system and wedge-shape lens made of the split-ring pairs show the negative refraction phenomenon.

並列關鍵字

double negative metamaterials ； split-ring resonator ； electromagnetic theory ； numerical simulation

參考文獻

Chapter 1:

[1] J. D. Jackson, Classical Electrodynamics, 3rd edition (Wiley, New York, 1999).

[2] K. R. Chu, Lecture Notes on Classical Electrodynamics (2012).

[3] J. B. Pendry, "Negative refraction," Contemp. Phys. 45, 191 (2004).

[4] V. G. Veselago, "The electrodynamics of substances with simultaneously negative values of ε and μ," Soviet Physics Uspekhi 10, 509 (1968).