Scientists Learn How to 'Bend' Lasers

The find could be used to "direct" lightning

  Laser experiments are yielding more and more surprising results

Experts from the University of Arizona in Tuscon (UAT) have managed a breakthrough in laser technology, as they have invented laser beams that can bend. The solution offers numerous practical applications, including the development of technologies that would allow lighting strikes to be turned away from large buildings, airports, power plants, government buildings, and other sensitive places. The remarkable thing is that expert Jerome Moloney's research team at UAT has already succeeded in manipulating light in the laboratory, bending lasers around corners with relative ease.

The beam that was used for the current experiments was made up of short laser pulses, which had the ability to travel very long distances without losing their focus. Laser physicists explain this trait by the fact that the beams manipulate the speed at which light travels through the air, making it move slower in the middle of the laser pulse, and faster at its edges. This creates a self-focusing effect in the beam and allows it to reach enormous distances without losing any of its density and focus in the process.

According to Moloney, this type of lasers can be manipulated with one of another kind, namely with an Airy beam. This one, which relies on the mathematical formulas created in the 19th century by astronomer George Biddell Airy, also shoots in pulses, but the first one is always stronger and carries most densities than the ones that follow. All the other ones are emitted half a wavelength out-of-step compared with the ones before. This creates a bending effect, in that the “tail” of the laser distorts towards a side, and the “head” moves in the opposite direction. The end result is a semi-circular-like beam.

Swiss physicist Jerome Kasparian, from the University of Geneva, said that, “Shaping these beams at such high intensity is really an impressive piece of experimental work.” He added that the amazing thing about the Airy beam was that it was not easily obstructed. If it encounters an obstacle, or something gets in the way of the beam, it will simply clear them and then retake its shape and self-focus. “It's really amazing, it will almost look like it has just passed straight through the obstacle. This makes them very well suited to atmospheric applications because they won't be blocked by raindrops,” he explained, as quoted by Nature.

Experts argue that the innovation could be used to devise new efficient techniques of constructing circuits. One possible application is a device that can etch intricate models on a glass support, allowing for the construction of integrated optical chips. “This is ideal for applications that combine compactness and complexity. Technology is at a point where this could be done soon, and if they succeed that would really be quite something,” Oxford University laser physicist Ian Walmsley concluded.

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By    10 Apr 2009, 07:47 GMT