光兆赫波段(THz)有著特別的物理特性,在各種領域的的應用具有潛力,而在兆赫波段的單光子研究更是待發展的領域,因此操控兆赫光波變為一重要的課題,如我們希望架設的HBT(Hanbury~Brown&Twiss)實驗中,就需要一塊50:50的分光片,但目前兆赫波段的光學元件較為缺乏,尤其目前市面上並沒有商業販售的兆赫波段偏振分光片,因此我們的目標為先嘗試自己發展與製作兆赫波段的偏振分光片. 目前各文獻中已有許多團隊給出不同的設計與構想,其中最簡單的設計為利用一兩不同折射率週期性的結構和布魯斯特角的物理特性來達成此一目標.我們以此概念為基礎,使用一容易取的的材料-紙張來製作,紙張為一便宜且對兆赫波段吸收不大的特性,是一適合用來製作兆赫光學元件的材料.實驗上我們利用時域光譜(TDS)來量測元件的表現與特性,並與理論模型作比較分析,但一般以超快脈衝方法產生的兆赫波頻寬較快comma因此文章最後我們也提出一理論的方法最佳化工作頻寬comma並給出數值解fs
It has been a great interest to control and manipulate THz wave due to its unique properties and various applications. In the emerging field of THz quantum optics, for example, one will need to split an incident THz wave in order to study the photon statistics. However, THz polarizing beam splitters are still rarely available on the market. The purpose of this thesis is thus to develop a THz polarizing beamsplitter using accessible materials. Inspired by an earlier theoretical work, we demonstrate a low-cost narrowband polarizing beamsplitter in the THz region. The beamsplitter is composed of alternating layers of paper and air. The incident THz beam, generated by exciting a biased semiconductor antenna with a femtosecond laser pulse, is tilted at a Brewster angle with respect to the first layer. We characterize the performance of the beamsplitter by terahertz time-domain spectroscopy. We also use genetic algorithm to propose a broadband THz beamsplitter.