Dissemination of IT for the Promotion of Materials Science (DoITPoMS)

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Summary

The basic features of diffraction and imaging have been presented in this package. When a wave, such as light, passes through a small aperture, it will be distorted. It will form a distinctive pattern on a screen, known as the diffraction pattern. This pattern contains information on the diffracting aperture (such as a mask or grating), with an inverse relationship in dimensions. The form of the intensity pattern can be predicted mathematically.

A lens can be used to form an image of the mask onto the screen. The diffraction pattern of the mask can be seen in the back focal plane of the lens. By forming the image from selected portions of the diffraction pattern in the back focal plane, particular information present in the image can be enhanced.

The theories involved can be applied to electrons and X-rays, as well as optics.