Laser pulses appear to travel faster than the speed of light

摘要

LIGHT travelling through a plasma can appear to move both slower and faster than what we refer to as "the speed of light" - 299,792,458 metres per second - without breaking any laws of physics. Clement Goyon at Lawrence Livermore National Laboratory in California and his team achieved this using a pair of lasers fired into a jet of hydrogen and helium plasma. One laser, called the pump beam, was 100,000 times more powerful than the other, called the probe beam. Each released a short pulse of light. At the spot where the pulses collided, the interference in the light created a wave throughout the plasma.