Dispersion is a phenomenon in which polychromatic light is decomposed into monochromatic light to form a spectrum. Dispersion can be achieved by using instruments such as prisms or gratings that act as dispersive systems. For example, after the polychromatic light enters the prism, because it has different refractive indices for light of various frequencies, the propagation directions of various colored lights have different degrees of deflection, so when they leave the prism, they are dispersed to form a spectrum.
