兆赫波波段金屬網狀帶通濾波器之偏振性和相位差研究

Abstract

本論文研究由不對稱十字架孔洞陣列形成之薄金屬帶通濾波器，對於不同偏極方向入射光該濾波器的穿透特性和衍生的相位差行為。我們改變十字架長、寬和週期三種結構，量測元件於兩個不同偏極方向(沿長軸與短軸)的穿透強度和相位差改變量。實驗與模擬結果可有定性上之吻合。我們發現不對稱十字架孔洞於不同偏極方向的穿透行為無法單用兩個正交矩形孔洞的穿透來做近似。此外，經過適當的設計週期性不對稱十字架孔洞陣列，基板上的薄金屬網狀濾波器可作為相位延遲片中的四分之一片來使用。

The paper investigates substrate-supported thin metallic band-pass filters perforated with asymmetric cross-shaped hole arrays. We vary the cross-shaped arm length, the width ,and the period of the cross-shaped hole arrays. We measure two polarized transmission spectra along the short and the long arm of the cross-shaped holes for each device. We also derive the phase shift of the filters. The data agree qualitatively with our simulation results. We find that the transmission characteristics of an asymmetric cross-shaped hole can not simply be explained by the transmission characteristics of two orthogonally arranged rectangular holes. Furthermore, we can obtain a quarter waveplate by properly designing the dimensions of the asymmetric cross-shaped holes.