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The success of the phase-contrast microscope has led to a number of subsequent phase-imaging methods. In 1952, Georges Nomarski patented what is today known as differential interference contrast (DIC) microscopy. [8] It enhances contrast by creating artificial shadows, as if the object is illuminated from the side.
The effect of the contrast transfer function can be seen in the alternating light and dark rings (Thon rings), which show the relation between contrast and spatial frequency. The contrast transfer function (CTF) mathematically describes how aberrations in a transmission electron microscope (TEM) modify the image of a sample.
The passage of many pairs of rays through pairs of adjacent points in the sample (and their absorbance, refraction and scattering by the sample) means an image of the sample will now be carried by both the 0° and 90° polarised light. These, if looked at individually, would be bright field images of the sample, slightly offset from each other ...
With the sample system built, all that is needed is an epifluorescence microscope and a CCD camera to make quantitative intensity measurements. This is a diagram of an example FLIC experimental setup with silicon, three oxide layers and a fluorescently labeled lipid bilayer (the yellow stars represent fluorophores.
This is the basis of the idea of phase contrast imaging. [2] As an example, consider the setup shown in the figure on the right. A schematic illustrating the ray optics of phase contrast imaging. A probe laser is incident on a phase object. This could be an atomic medium such as a Bose-Einstein Condensate. [3]
Often the contrast reduction is of most interest and the translation of the pattern can be ignored. The relative contrast is given by the absolute value of the optical transfer function, a function commonly referred to as the modulation transfer function (MTF). Its values indicate how much of the object's contrast is captured in the image as a ...
Like differential interference contrast microscopy (DIC microscopy), contrast is increased by using components in the light path which convert phase gradients in the specimen into differences in light intensity that are rendered in an image that appears three-dimensional. The 3D appearance may be misleading, as a feature which appears to cast a ...
Fluorescence interference contrast microscopy; Interference reflection microscopy; See also. Phase contrast microscopy; References