Optical device that transmits a mechanically selectable narrow band of wavelengths
of electromagnetic radiation chosen from a wider range of wavelengths available at
the input.
Note:
To spatially separate the wavelengths, a monochromator can use either the
phenomenon of optical dispersion in a prism, or that of diffraction using a grating.
Source:
PAC, 2007, 79, 293
(Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006))
on page 372