Obstacle-passing bending laser to fish for lightning
Published 10 April, 2009, 11:55
A special laser beam that can curve and pass obstacles may be used to direct lightning and make future particle accelerators smaller.
A team of scientists at the University of Arizona headed by Professor Pavel Polynkin combined a high energy pulse laser beam, which can be used to ionize gases in the atmosphere to create a plasma channel, with a special beaming technique. The technique called Airy beam – named after George Biddell Airy, a 19th century astronomer who discovered the mathematics behind the phenomenon – allows bending laser, reports Nature journal.
An Airy beam is actually created by complicated interference of a light pattern, created by a laser passing through a digital screen, carefully phasing the light waves. The resulting beam, or rather a pattern of one bright area surrounded by small dim patches, has several curious characteristics.
For one, it bends by several millimetres for every several dozen centimetres it travels. Combined with an intensive laser, the technology can create curved plasma channels.
Jerome Moloney from the University of Arizona believes this can be used to guide lightning away from power plants, tall buildings, and other facilities.
More over, Airy beams have a self-healing property: If an obstacle blocks part of the beam, it re-shapes and focuses itself again later on its path.
“It's really amazing, it will almost look like it has just passed straight through the obstacle," says Jérôme Kasparian, a physicist at the University of Geneva, Switzerland. "This makes them very well suited to atmospheric applications, because they won't be blocked by raindrops."
Ian Walmsley, a laser physicist at Oxford University, says the technology may have application in novel particle collisions that use a laser beam travelling through plasma rather than an electric field to propel charged particles.
Another possible area is the manufacturing of integrated optical chips, which use light pulses instead of electric current to process information.
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