angular dispersion

American  

noun

Optics.

1. a measure of the angular separation of light rays of different wavelength or color traversing a prism or diffraction grating, equal to the rate of change of the angle of deviation with respect to the change in wavelength.

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Example Sentences

Instead of one prism two or three may be used, giving an angular dispersion of the spectrum two or three times respectively greater than that which would be given by only one prism; consequently to obtain a given length of spectrum with the increased dispersion, the focal length of the lens used to focus the image on the screen may be diminished.

From Project Gutenberg