In optics, the refractive index of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium.
Thomas Young coined the term index of refraction in 1807.
Diamonds have a very high refractive index of 2.417.
A split-ring resonator array arranged to produce a negative index of refraction for microwaves
In optical mineralogy, thin sections are used to study rocks. The method is based on the distinct refractive indices of different minerals.
Light, visible light, or visible radiation is electromagnetic radiation that can be perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 terahertz. The visible band sits adjacent to the infrared and the ultraviolet, called collectively optical radiation.
A triangular prism dispersing a beam of white light. The longer wavelengths (red) and the shorter wavelengths (green-blue) are separated.
Beam of sun light inside the cavity of Rocca ill'Abissu at Fondachelli-Fantina, Sicily
Due to refraction, the straw dipped in water appears bent and the ruler scale compressed when viewed from a shallow angle.
Hong Kong illuminated by colourful artificial lighting
