光源同調性量測與其時變效應之分析

Abstract

光源同調性影響著雷射光源的許多重要性質，像是頻寬、對比以及光斑。全像術、光碟片儲存等基於干涉的應用之中，光源同調性決定了影像品質。為了要瞭解雷射光的同調性，因此需要可靠的同調性測量方法。本研究分成以下兩個部分，第一部分介紹利用繞射元件來光源同調性的測量方法。雖然第一部分已經介紹了光源同調性的測量術，但是因為光源的隨機性，所測得的同調性會隨時間變化，在第二部分，進一步加入光源的隨機性，利用隨機漫步理論來計算光源同調測量的時變效應，實驗結果可定性的驗證理論的正確。 本論文整理了時下的同調性量測技術，並分析了光源在測量過程中會出現的隨機效應。希望本研究的統計結果可做為未來相關研究之參考。

Coherence is an important property of light field, especially in the interference based applications namely bandwidth, contrast and speckle. To fully realize the co-herence property of light field a robust coherence measurement technique is required. This research is split into two parts. In first part, some reliable coherence measure-ment techniques are proposed. These techniques are based on diffraction theory. Though the measurement techniques are presented, the measurement result is still suffering from the time dependent problem. Hence, the randomness of optical system is taken into consideration in second part. The measured degree of coherence is ana-lyzed by utilizing the random walk theory. The random walk theory can tackle the time verifying property of degree of coherence easily. Besides, the simulation and experi-mental results are in good agreement with the theoretical prediction. In this research, the modern degree of coherence measurement techniques are summarized. The time verifying property is also well analyzed. The statistical result here can be referenced for following researchers.