Design Nomenclature / Light & Optics
Dispersion
Also called chromatic dispersion, chromatic aberration
This entry has not been translated yet and is shown in English.
The dependence of refractive index on wavelength, so a single refraction sends each wavelength off at a slightly different angle. It is what a prism does, what builds a rainbow, and — inside a lens — what chromatic aberration is: the same image formed at slightly different scales per colour.
Not to be confused with
- RefractionThe bending of light as it crosses between media of differing index, because its phase velocity changes; Snell's law fixes the new angle from the ratio of the two indices. It is what makes a submerged rod look broken and what gives a lens any power at all.
- DiffractionThe spreading and interference of light as it passes an edge or aperture — a wave effect rather than a ray one. It sets the resolution floor of any optical system, puts the star points on a stopped-down aperture, and produces the rainbow sheen on a disc's pitch.