Editing Diffraction (section)

== Patterns ==
[[File:Diffraction on elliptic aperture with fft.png|thumb|The upper half of this image shows a diffraction pattern of He-Ne laser beam on an elliptic aperture. The lower half is its 2D Fourier transform approximately reconstructing the shape of the aperture.]]
Several qualitative observations can be made of diffraction in general:
* The angular spacing of the features in the diffraction pattern is inversely proportional to the dimensions of the object causing the diffraction. In other words: The smaller the diffracting object, the 'wider' the resulting diffraction pattern, and vice versa. (More precisely, this is true of the [[sine]]s of the angles.)
* The diffraction angles are invariant under scaling; that is, they depend only on the ratio of the wavelength to the size of the diffracting object.
* When the diffracting object has a periodic structure, for example in a diffraction grating, the features generally become sharper. The third figure, for example, shows a comparison of a [[Double-slit experiment|double-slit]] pattern with a pattern formed by five slits, both sets of slits having the same spacing, between the center of one slit and the next.