背景光存在下的相衬法原理分析

为了更好地观察弱相位物的位相,在考虑背景光的情况下,对任意相位物体的相衬成像过程进行严格的数学推导及分析,得到有背景光时的相衬法成像光强普遍表达式。结果表明,有背景光时的相板相移量及其透过率存在最佳值;若采用CCD接收图像,弱相位物的最小可观察相位变化量达1.9mrad。这为弱相位物体的精确测量提供了有力的数学论证。

Analysis of phase-contrast method with background light

In order to observe weak phase objects, the phase contrast imaging of any phase objects with background light was strictly analyzed by mathematics. The general expressions of the image intensity, the best phase shift and the best transmittance of a phase plate were obtained. If the images are received by CCD, the phase variation of phase object that can be tested is about 1.9mrad. These will provide the mathematical demonstration for observing and testing weak phase objects.