電磁理論模擬研究超穎材料及拓樸光子晶體之新穎特性

Novel properties of metamaterials and topological photonic crystals studied by electromagnetic theoretical simulations

詹勳奇(Hsun-Chi Chan)

指導教授 ： 郭光宇

國立臺灣大學/理學院/物理學研究所/博士(2018年)

https://doi.org/10.6342/NTU201801793

摘要

利用電漿奈米球、光子晶體、及電磁超穎材料來調控光的傳播及偏振，近幾十年來在光子學領域引起了極大的關注。在本論文中，我們通過有限元方法研究了該領域許多的有趣題目如下。首先，我們提出了一種新穎的左手材料，它是由一對在近紅外區域的直立開口環組成。其次，研究了由晶格常數稍大於光波長的卍字形金洞，顯示了可觀的非零繞射級中之極化轉換和強圓二色性。第三，我們研究了置於手徵介電非對稱球殼附近的手性分子的自發放射的輻射衰減率。結果顯示，左手和右手分子會引起衰變速率的顯著差異。
另一方面，近來拓撲光子學也引起了很多關注，因為這些系統表現出迷人的波傳輸特性。所以，我們通過計算帶結構，貝里曲率，陳數，及邊界態之數值模擬，研究了具有同時破壞時間反演對稱和宇稱的二維光子晶體中的拓撲相位。特別地，可以通過簡單的旋轉柱子來調控拓樸相變，例如從量子異常霍爾相到量子谷霍爾相。

關鍵字

表面電漿超穎材料 ； 負折射率 ； 繞射級 ； 手徵材料 ； 拓樸光子學

並列摘要

Manipulation of the propagation and polarization of light using plasmonic nanoparticles, photonic crystals and electromagnetic metamaterials has received enormous attention in the vibrant field of photonics in recent decades. In this dissertation, we have investigated a number of fascinating topics in the field via finite element method as follows. First, we propose a novel left-handed material composed of an array of simple upright split-ring pairs working in the near infrared region. Second, a square lattice of swastika nanoholes made of gold film with lattice constants being slightly larger than light wavelength are explored, showing the polarization conversion and strong circular dichroism in non-zero diffraction orders. Third, we study the radiative decay rate of the spontaneous emission of a chiral molecule located near a dielectric spherical particle with a bi-isotropic nonconcentric spherical shell. It turns out that the left and right chiral molecule would cause significant difference in the decay rate.
On the other hand, topological photonics also have attracted much attention recently because these systems exhibit fascinating wave transport properties. Therefore, we study topological phases in a 2D photonic crystal with broken time and parity symmetries by performing calculations of band structures, Berry curvatures, Chern numbers, and also numerical simulations of light propagation in the edge states. Specifically, phase transitions among these topological phases, such as from quantum anomalous Hall phase to quantum valley Hall phase and vice versa, can be engineered by a simple rotation of the rods.

並列關鍵字

plasmonic metamaterials ； negative index of refraction ； diffraction order ； chiral media ； topological photonics

參考文獻

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