The phase and the group velocity of light propagating in conventional optical media cannot exceed the speed of light in vacuum. However, in so-called epsilon-near-zero (ENZ) materials, light exhibits an infinite phase velocity and a vanishing group velocity for a particular color (frequency). The phase and the group velocity of light propagating in conventional optical media cannot exceed the speed of light in vacuum. However, in so-called epsilon-near-zero (ENZ) materials, light exhibits an infinite phase velocity and a vanishing group velocity for a particular color (frequency). Optics & Photonics Soft Matter Phys.org – latest science and technology news stories
Scientists achieve optical control of phase and group velocities in everyday liquids
