Light brought to complete halt for one minute

Last Updated: Fri, Jul 26, 2013 07:12 hrs

London: The fastest thing in the universe - Light, was brought to a halt for a record-breaking minute.

Thomas Krauss at the University of St Andrews, UK said that the feat was indeed a major milestone, as one minute is extremely a long duration for light to come to a pause.

The feat could allow secure quantum communications to work over long distances, according to New Scientist.

Physicists managed to slow down light, which normally travels at just under 300 million metres per second in a vacuum, to just 17 metres per second in 1999 and then halt it completely two years later, though only for a fraction of a second.

Researchers kept it still for 16 seconds using cold atoms earlier this year.

To break the minute barrier, George Heinze and colleagues at the University of Darmstadt, Germany, fired a control laser at an opaque crystal, sending its atoms into a quantum superposition of two states.

This made it transparent to a narrow range of frequencies.

Heinze's team then halted a second beam that entered the crystal by switching off the first laser and hence the transparency.

The storage time depends on the crystal's superposition. A magnetic field extends it but complicates the control laser configuration.

Heinze's team used an algorithm to "breed" combinations of magnet and laser, leading them to one that trapped light for a minute.

They also used the trap to store and then retrieve an image consisting of three stripes.

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