Dispersion by diffraction grating is the phenomenon where a beam of light passing through a grating is separated into its component colors, or wavelengths. This is due to the diffraction of light as it passes through the narrow slits on the grating.
A diffraction grating is made up of a series of closely spaced parallel lines, or slits, that act as obstacles to the passing light. When the light encounters these slits, it is diffracted and spreads out into a spectrum of colors.
The spacing of the grating, also known as the grating constant, determines the angle at which the different colors are dispersed. A smaller spacing will result in a wider dispersion angle, while a larger spacing will result in a narrower dispersion angle.
Diffraction gratings are commonly used in spectroscopy, which is the study of the interaction between light and matter. They are also used in optical instruments such as spectrometers and monochromators to analyze and separate different wavelengths of light.
Dispersion by diffraction grating is based on the diffraction of light, while other forms of dispersion, such as refraction and reflection, are based on the bending of light. Diffraction grating dispersion is also more precise and can separate light into a larger number of distinct wavelengths compared to other methods.