When light passes from one medium (material) to another it changes speed. This is because the speed of a wave is determined by the medium through which it is passing. When light speeds up as it passes ...

A property of a material that changes the speed of light, computed as the ratio of the speed of light in a vacuum to the speed of light through the material. When light travels at an angle between two ...

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.

The article develops coordinate-invariant methods to calculate reflection and refraction of plane monochromatic waves at the plane boundary between two isotropic and an isotropic and an anisotropic ...

Based on highly accurate optical interferometry and fundamental quantum calculations, researchers in the US are developing an improved definition of the SI unit for pressure that will consign the ...

The negative refraction of electrons in graphene has been seen for the first time in experiments done by physicists in the US. The work represents an important advance in the fabrication of graphene ...

ABSTRACT: The resemblance between the equation for a characteristic hypersurface through which wavefronts of light rays pass and optical metrics of general relativity has long been known.