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A highly periodic arrangement of finely spaced, parallel apertures or grooves or slits is
called a diffraction grating. These parallel elements are used to diffract light, generally
both separating and spreading different wavelengths or colors. Diffraction gratings are
manufactured on flat or curved surfaces according to their use.
Diffraction gratings are used in spectrographic equipment (spectroscopes, spectrophotometers,
monochromators, spectrographs, spectrometers, etc.) as the principal optical element to separate
light into its component wavelengths (frequencies) by diffracting them at various angles. Gratings
also are used in some lasers that are capable of emitting a coherent output at more than one
wavelength. In this application the grating is used to select a desired narrow wavelength range for
the laser output.
Present-day gratings consist of equidistant line rulings on a flat glass plate (transmission grating)
or on a flat mirror (reflection grating). Depending on the application, the number of lines per millimeter
typically ranges from less than one hundred to several thousand.
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Gratings
- Diffraction Grating
- Double Slit Diffraction
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