| phase_velocity_vs_group_velocity | ||
| mp21k | Two types of velocity are used to describe the propagation of a wave in a dispersive medium: the phase velocity and the group velocity. The phase velocity is the speed at which light of a single wavelength moves. However, a pulse of light contains a range of wavelengths that all move at different speeds, so the group velocity is defined as the speed at which the pulse itself moves. | 050320 |
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Photonic crystal slows down light http://physicsweb.org/articles/news/9/3/10/1 ...reducing the group velocity of light by a factor of 100... |
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