利用空間光調制器量測光場同調性之研究

Abstract

光場的空間同調性越來越重要，其描述了波場(wavefled)的統計特性。而這樣的性質有著重要的影響，像是在全像術或是數位全像顯微鏡會因為同調性的不同而有不同的成像品質。而Van Cittert-Zernike 理論(V.C.Z 理論)，是用來描述光源同調性的重要理論。一般對V.C.Z理論的量測方式是使用楊氏雙狹縫干涉(Young's double slits interference)，需要不斷的更換狹縫去對光場取樣，但效率很低，在此論文提出利用空間光調制器，量測光源的同調性。因為空間光調制器是可以利用電腦所控制，因此可以提升量測效率。

The coherence is an important property of light. it affects the image quality in many field like digital holographic microscopy. In the coherence theory, there is a significant theorem to describe the distribution of the spatial coherence: Van Cittert -Zernike theorem. It describes the statistical properties of the wavefield. In general, it is measured by the Young’s double slits interferometer. But it is not constant over the light field. In order to describe the coherence distribution, it must sample the light field with different spacing of the slits. So, this approach is time-consuming . In this study, we use the spatial light modulator (SLM) to measure the spatial coherence. The spatial light modulator could modulates the intensity of the light with the polarizer and analyzer. Because the SLM is controlled by the computer, the slits could be easily changed. This adaptive method would improve the efficiency of the measurement.