以平行化時域有限差分法研究多段轉折奈米天線結構

Abstract

時域有限差分法已被廣泛的運用在光電電磁模擬上，我們利用Ｃ++語言建構了一個三維時域有限差分法模擬器，並且擁有平行化功能，利用多台電腦透過訊息傳遞介面協定，以減少計算的時間。 本論文主要分析四種多段轉折奈米天線結構與陣列。我們先討論單個的多段轉折奈米天線，以一個寬頻的正向入射電磁波作為波源得到波長0.3 微米到4.0 微米區間的響應，並且計算天線間隙的局部電場強度增強及其相對應的共振波長，改變天線的臂長並觀察其對頻譜所造成的影響，接著，我們將天線擺放成陣列來觀察其特性，並且比較其與單個的多段轉折奈米天線的不同，最重要的研究結果發現，陣列的週期長度對天線陣列的頻率響應有重要的影響，這些將會在後面被討論，對於有更多轉折或更長臂長的天線，長波長的寬頻特性將會被觀察到。

The finite-dierence time-domain(FDTD)method has been widely used in computational electromagnetics. We construct aparallelized three-dimensional(3-D) FDTD simulator in C++ language and several computers are connected to speed-up the computations by using the message passing interface(MPI) protocol in order to reduce the simulationtime. In this research, the Multi-Bent-Section Nano-Antennas (MBSNAs) and arrays of four dierent structures are numerically studied. The single Multi-Bent-Section Nano-Antennas are first investigated by applying a broadband normally incident plane wave to obtain responses in the wavelength range from 0.3 um to 4.0 um. The electriceld enhancement in the gap of antenna and corresponding resonant wavelengths are calculated and the influence of dierent varied antenna arm widths on the enhancement spectrum is studied. Then the corresponding four different arrays are investigated and compared with the single antennas.The enhancement spectra of the arrays are found to depend critically on the array period lengths and are examined in detail. For antennas with more sections or longer arms, wide-band characteristic in the long wavelength regime is observed.