相位凸顯成像的探討

Investigation of Phase-Contrast Imaging

陳淑萍(Shu-Ping Chen)

指導教授 ： 游漢輝

國立中央大學/理學院/光電科學研究所碩士在職專班/碩士(2007年)

摘要

本論文主要為闡述相位凸顯成像的原理，並以實驗佐證之。由於相位凸顯成像的原理已經很成熟[ 1-6 ]，所以本論文專注在顯示它的實驗設計和擺設。這個設計的重點在於其擺設 (experimental layout) 簡單，但卻能清楚的顯示出本論文原理部份的每一個環節的要求和結果。
本實驗的核心元件為一件相位變化量不大的相位型物 (phase object) 以及一片上有一很小的相位延遲點 (phase delay spot) 的片子。這兩件元件，市上都沒有現貨，所以我們要自行製作。結果前者由楊宗勳教授實驗室中之王良峰同學製出，至於相位延遲片則由李正中主任所領導的薄膜中心代行製出。我們一共製作了兩類相位延遲片，第一類的製作原理依循一般DOE的觀點，第二類則依循Collier等人之觀點來製作。所以本論文的另一個目的為檢視Collier等人的觀點正確與否，實驗結果顯示他們這個觀點確實有待商確。
在前述兩類延遲片中，我們對每一類均各製作了兩片，一片的相位延遲量為 ，另一片為 。所以一共四片。相位延遲量為 的延遲片所產生的效果稱為明像效果。而相位延遲量為 的延遲片所產生的效果稱為暗像效果。由於這些「物」和「延遲片」都不一定達到原來我們所開出的規格，因此實驗結果並不十分完美，它們雖然仍然能把透明的物體顯現出來，不過，對於從明像效果變成暗像效果的轉變則沒有得到良好的結果。

關鍵字

相位凸顯

並列摘要

The main theme of this thesis is to present a simple setup to demonstrate the principle of imaging with phase-contrast technique. Since the principle of this technique is mature and can be found in literatures [ 1-6 ], we focus in this work on the design of the experimental setup. However, an outline of the principle is included here for completeness and showing how a transparent object becomes obseualle. The including of the principle also helps understand how the experimental setup achieve this goal and how the steps in the theory are realized in it.
In the demonstration of this technique, we need a phase object of small phase variation and a small transparent spot with specific phase delay. Since these elements were not available in the stock of the major manufacturers, they were prepared by the laboratories of our Institute. We prepared two kinds of phase-delayed spots in this investigation. The first kind was made according to the current theory of diffractive optics, while the second kind was made according to the viewpoint of Collier at al (Ref 12). And, for both kinds of the phase-delayed plates, two plates were made. The amount of phase delay of the first kind is and that of the second one is . It is know that the fist kind of phase-delayed spot produces a bright image against the background, while the latter produces a dark image. Experimental results have shown that the phase objects do become observable in the present experimental conditions. However, since neither the object nor the phase-delayed spot, had met the design specification perfectly, the changing from a bright image to a dark image only took place in some part of the image. Since these objects had not met the specification in the theory accurately, the final experimental results are not very distinct. They nevertheless show the effect qualitatively.

並列關鍵字

Phase-contrast

參考文獻

1. F.Zernike "Das PhasenKontrastverfahren bei der Mikroskopischen beobachtung," Z.Tech.Phys. 16-454(1935)

2. Nemoto and A. Takahashi, "Methods of improving the images in phase-contrast microscopy: theory and computer simulation," J. Opt. Soc. Am. A 8, 511- (1991)

3. T. E. Gureyev, Y. I. Nesterets, D. M. Paganin, and S. W. Wilkins, "Effects of incident illumination on in-line phase-contrast imaging," J. Opt. Soc. Am. A 23, 34-42 (2006)

4. P. R. T. Munro and P. Török, "Effect of detector size on optical resolution in phase contrast microscopes," Opt. Lett. 29, 623-625 (2004)

5. C. Mann, L. Yu, C. -M. Lo, and M. Kim, "High-resolution quantitative phase-contrast microscopy by digital holography," Opt. Express 13, 8693-8698 (2005)