二維非均勻極化光之合成

Abstract

非均勻極化光近年來因其焦平面特別的強度分佈特性，所以被廣泛的研究討論，可運用於微粒補捉、材料處理、高解析度光學顯微鏡等領域。其中最知名的非均勻極化光為軸向對稱光，包含了徑向對稱極化光和角方向對稱光，這二兩種光都有這甜甜圈形狀的強度分佈，而不同的對稱極化分佈則可以在焦平面上得到不同的場分佈，例如徑向對稱極化光則可以得到較小的光點。具備達到或超越向量繞射限制的技術和在焦平面場分佈設計成為我們研究和發展的重心。藉由圓極化和相位調變器，可以將軸向對稱光拓展成為空間非均勻的任意極化光場。 基於以上論述，在此論文中，我們的目標是建立一光學系統來合成空間上非均勻極化光，這使我們可以在空間上方便的設計不同的極化分佈。為了可以動態的即時控制，我們採用干涉式的架構來合成均勻極化光。合成系統的穩定性將藉由我們校正技術來調整，而這個技術主要是利用系統中光渦的干涉圖像。最後這個方法的可行性，將由實驗的結果得到驗證。

Recently inhomogeneous polarized beams have been widely noticed due to their novel focal behavior for optical trapping, material analysis, and high-resolution imaging. The most well-known inhomogeneous polarizations include radial and azimuthal symmetry associated with donut-shaped pupil irradiance. The idea of extending cylindrical vector beams to arbitrary inhomogeneous polarized beams was presented by using the circular polarization with phase modulation method. This study was aimed at reaching vectorial diffraction limit and focus spot shaping. In the thesis, a home-built optical configuration to synthesize the spatially inhomogeneous polarized beams was demonstrated. The infereometric scheme based on dynamic phase control was adopted to synthesize the spatially inhomogeneous polarizaed beam in a effective and simple way. Moreover, the characteristics of the sharp focus was analysed by a unique eight-zone segmentation of polarization states, which can be further applicable for the optical encryption. In addition, the stability as well as phase calibration of synthesis was also discussed.