Electromagnetic radiation — these interactions include the Faraday effect and the Kerr effect. In refraction, a wave crossing from one medium to another of different density alters its speed and direction upon entering the new medium. The ratio of the refractive indices of the media determines the degree of refraction, and is summarized by Snell's law. Light of composite wavelengths (natural sunlight) disperses into a visible spectrum passing through a prism, because of the wavelength-dependent refractive index of the prism material (dispersion); that is, each component wave within the composite light is bent a different amount. EM radiation exhibits both wave properties
Negative refraction propagation direction of the light, thus the sign of "n" must be chosen to match the physical situation. The principal symptom of negative refraction is just that – light rays are refracted on the "same" side of the normal on entering the material, as indicated in the diagram, and by a suitably general form of Snell's law. Negative refraction Negative refraction is the name for an electromagnetic phenomenon where light rays are refracted at an interface in the reverse sense to that normally expected. Such an effect can be obtained using a metamaterial which has been designed to achieve a