Fast and slow light made easy
Amazing: Light travels at a speed of 300 million metres per second in a vacuum, but in recent years physicists have managed to slow laser pulses down to speeds of metres per second - or to bring them to a complete halt - in ultracold gases. In similar experiments physicists have observed superluminal or faster-than-light pulse propagation. These effects have also been observed in crystals at cryogenic temperatures and in "hot" gases. Now Matthew Bigelow, Nick Lepeshkin and Robert Boyd have observed the same effects in a much simpler system - a crystal at room temperature.
Read the rest on Physics Web