It is found in Aldis's “Tract on Double Refraction,” p. 7, in Preston's “Theory of Light,” third edition, p. 328, and in Basset's “Treatise on Physical Optics,” p. 115.

When a wave or light ray moves from one medium to another its speed changes. The direction of the ray may also change. This property of waves is called refraction and commonly occurs with light rays.

Light changes speed as it passes from one medium to another. This is called refraction. The frequency of light does not change as it refracts. The refractive index of a material is a measure of ...

The pressure exerted on a surface when it is struck by light is tiny ... has only been indirect far-field evidence for negative refraction and superlensing at visible frequencies.

Negative refraction is based on the equations developed in 1861 by Scottish physicist James Maxwell. All known natural materials have a positive refractive index so that light that crosses from one ...