調變光源空間同調性之研究

Abstract

同調性一直是光學系統分析中被探討的一大重點，因為此項特性會影響系統中光場干涉的情形。近年來部分同調光的應用越來越被重視，因為雷射過於同調的特性將會導致成像系統產生雷射散斑，而部分同調光可以良好地改善此現象。此外，在相位還原的領域中，加入光源同調特性的考量，也能讓其擁有較好的還原品質。 因此，本論文的研究目標致力於光源同調性的操控。目前部分同調光的產生，主要是透過增加同調光源的隨機性來達成。而其中最主流的方式又分為兩種：利用旋轉散光片和光源調製器(SLM)來賦予光源的隨機性。本研究將嘗試藉由旋轉散光片與光源調製器(SLM)來調變光源同調程度，並比較其中的優劣。

The coherent properties of light sources are often a focal point in the analysis of optical field, because it will influence the interference phenomenon in many optical systems. In recent years, partially coherent light becomes more and more important, since the application of highly spatially coherent lasers in some optical imaging systems will yield laser speckles which tend to mask the image information. The coherent property of light source is also considered in the phase retrieval technology so that the phase information will be retrieved better. Therefore, in this thesis, we aim to manipulate the degree of coherence of light. Frequently methods nowadays to form a partially coherent light are using a rotating diffuser or a spatial light modulator (SLM). In this study, we will try to get different degree of spatial coherence of laser by using rotating diffusers and a phase-only SLM.