體積全像透鏡之研製及其在光學圖形辨識的應用

Abstract

本論文主要在探討以全像技術來製作光學透鏡的各種特性與分析，並將其應用於光學資訊處理中。首先，我們由全像原理出發介紹全像透鏡的設計與分析，並利用純量繞射理論來探討體積全像透鏡執行光學圖案傅氏轉換的特性；其中，我們以一階波恩近似法則來分析低調制比的體積全像透鏡，從而得到圖案在全像透鏡等效傅氏面上的分佈與設計參數之間的關係；然後，根據理論的分析與討論，我們設計光學實驗以驗證之。最後，我們將所製作完成的體積全像透鏡應用於一個光學圖案辨識系統中，以執行圖案的辨識。

In this thesis, we investigate our theoretically and experimentally the properties of holographic lens which was fabricated by volume holographic technique. Firstly, we give a brief introduction of designing and analyzing holographic lens by using principle of basic holographic recording technique. Secondly, the Fourier transformation properties of a volume holographic lens are derived by using scalar diffraction theorem. By using the First-order Born’s approximation, the distribution of the filed in the effective focal plane of the holographic lens with low modulated refractive-index grating can be derived. The results show that the observed field of view of the Fourier transformation of the input image on focal plane is limited by the Bragg condition of the volume hologram. The Bragg condition is a function of the thickness of the lens, the recording angle between two writing beams, and the mismatched factor between the input and output plane. The computer simulation and optical experiments were demonstrated and compared. As a result, we can find optimum condition of a volume holographic lens for application in our optical information processing system. Finally, volume holographic lens and converged match filter are utilized to construct an optical pattern recognition system. We can demonstrate that the holographic lenses are suitable for optical information processing applications.