Light bends when travelling through a concentration gradient of sugar in water. The top layer of liquid is pure water while the bottom layer is concentrated sugar water. In these layers, there is no ...

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 ...

Physicists at Harvard University in the US have built a silicon waveguide that exhibits a refractive index of, or close to, zero when operating at near-infrared telecom wavelengths. The waveguide can ...