不同厚度之金屬光柵於紅外線波段之異常穿透率研究

Abstract

週期性的結構於光學特性的研究由來已久，其異常的穿透現象的成因，至今仍然眾說紛紜。其中一維金屬光柵對於不同方向的極化波，所造成的效應較二維週期性結構更為複雜。 在本論文中，我們藉由兩種不同的光阻加上電子束顯影系統，去定義出我們的一維光柵圖型，並藉由濕蝕刻製造出底切結構，最後蒸鍍上不同的金屬，接著再利用紅外線光譜分析儀去量測我們的結構。於兩種不同極化方向下，我們從實驗的頻譜中去分析波段的上升下降趨勢與並解釋異常穿透點背後所代表的物理原因。

The optical properties of periodical structure have been studied for a long time. The reason to anomaly of transmission spectrum was not well-discovered. For polarized incident light, the electromagnetic wave excited around one-dimensional metallic grating is more complicated than two-dimensional structure. In the thesis, we took usage of e-beam lithography system and two kinds of photoresist to define the pattern of grating. The undercut structure was fabricated with wet etching and the metallic grating was deposited with evaporation. The incident light was polarized in TE and TM modes, and the transmission spectrum of sample was measured by Fourier transform infrared spectrometer. We analyzed rising and descending trends of wave in the spectrum and tried to explain the underlying physics of extraordinary transmission points.