- Chromatic dispersion refers to dispersion according to colour.
- Chromatic dispersion is the result of the relationship between wavelength and refractive index.
- When light propagates from one medium (such as air) to another (such as glass or water) every wavelength of light is affected to a different degree according to the refractive index of the media concerned. As a result, each wavelength changes direction by a different degree. In the case of white light, the separate wavelengths fan out with red on one side and violet on the other.
- A familiar example of chromatic dispersion is when white light strikes raindrops and a rainbow of colours become visible to an observer.
- As light first enters and then exits each raindrop, it separates into its component wavelengths which the observer perceives as distinctly separate colours.
- Remember that wavelength is a property of electromagnetic radiation, whilst colour is a feature of visual perception.