Hot air guides laser beams

摘要

A channel of hot air could enable high-power laser beams to travel through the atmosphere over long distances - which might be useful for applications such as communications. High-power beams cannot be precisely focused over many kilometres, because the surrounding air absorbs and distorts the radiation. To solve this problem, Howard Milchberg and his colleagues at the University of Maryland in College Park created a conduit in air for the laser. They fired a square-shaped array of four intense, low-power light bursts. The dissipating shots left a channel of hot, dense air, through which the researchers then fired a powerful, focused laser beam. The team showed that the air channel guided the beam through 70 centimetres of air, and calculated that this waveguide could work over longer distances.