A monochromator usually consists of a dispersive element such as a diffraction grating or a prism, and a mechanism to select the desired wavelength. The dispersion element splits the incoming light into its constituent wavelengths, and a slit or a series of slits then allows only the desired wavelength to pass through. The ability to select specific wavelengths with high precision makes monochromators invaluable in spectroscopy and other analytical techniques.
