: While lasers have been used before to send information to satellites, this relatively new discovery is quite fascinating. Fibre optic cables are usually preferred due to having a high refractive index, and with fibre optic cables being encased in material having lower refractive index, it is possible to reflect the light back to the core of the cable, preventing the beam from losing focus. Now researchers are trying to do the same thing with air. How? Read more to figure it out...Focusing the beam
: Milchberg and colleagues' made the equivalent of an optical fibre out of air by generating a laser with its light split into a ring of multiple beams forming a 'pipe'. They used very short and powerful pulses from the laser to heat the air molecules along the beam extremely quickly. Such rapid heating produced sound waves that took about a microsecond to converge to the centre of the pipe, creating a high-density area surrounded by a low-density area left behind in the wake of the laser beams.Air 'Pipe'
: "A microsecond is a long time compared to how far light propagates, so the light is gone and a microsecond later those sound waves collide in the centre, enhancing the air density there," says Milchberg. The lower density region of air surrounding the centre of the air waveguide had a lower refractive index, keeping the light focused. "Any structure [even air] which has a higher density will have a higher index of refraction and thereby act like an optical fibre," says Milchberg.The findings
: The researchers found the signal was 50 per cent stronger than a signal obtained without an air waveguide. The findings show the air waveguide can be used as a "remote collection optic," says Milchberg. "This is an optical fibre cable that you can reel out at the speed of light and place next to [something] that you want to measure remotely, and have the signal come all the way back to where you are."
Article link: http://www.abc.net.au/science/articles/2014/07/23/4049345.htm?topic=energy
Research paper : http://www.opticsinfobase.org/optica/abstract.cfm?uri=optica-1-1-5
Additional link: http://www.sciencedaily.com/releases/2014/08/140819125946.htm
Phys.org link: http://phys.org/news/2014-07-optical-cables-thin-air.html
Main pic: from abc.net.au
. Additional pics http://news.discovery.com/tech/gear-and-gadgets/optical-fiber-made-out-of-thin-air-140723.htm
and http://www.wired.co.uk/news/archive/2014-07/23/optical-fibres-made-from-air #science #technology