Scientists use rogue laser waves to build better light sources

March 7th, 2009 - 5:41 pm ICT by ANI  

Washington, March 6 (ANI): Scientists are putting rogue laser waves to work in order to produce brighter, more stable white light sources, a breakthrough in optics that may pave the way for better clocks, faster cameras, and more powerful radar and communications technologies.

The rogue waves of light, rare and explosive flare-ups that are mathematically similar to their oceanic counterparts, have been developed by a group of researchers at the University of California, Los Angeles (UCLA).

Rogue bursts of light were first spotted a year ago during the generation of a special kind of radiation called supercontinuum (SC).

SC light is created by shooting laser pulses into crystals and optical fibers.

Like the incandescent bulb in a lamp, it shines with a white light that spans an extremely broad spectrum. But unlike a bulbs soft diffuse glow, SC light maintains the brightness and directionality of a laser beam.

This makes it suitable for a wide variety of applications - a fact recognized by the 2005 Nobel Prize in Physics, awarded in part to scientists who used SC light to measure atomic transitions with extraordinary accuracy.

Despite more than 40 years of research, SC light has proven to be difficult to control and prone to instability.

Though rogue waves are not the cause of this instability, the UCLA researchers suspected that a better understanding of how noise in SC light triggers rogue waves could improve their control of this bright white light.

Rogue waves occur randomly in SC light and are so short-lived that the team had to employ a new technique just to spot them.

By tinkering with the initial laser pulses used to create SC light, Solli and his team discovered how to reproduce the rogue waves, harness them, and put them to work.

His results demonstrate that a weak burst of light, broadcast at the perfect tickle spot, produces a rogue wave on demand.

Instead of disrupting things, it stabilizes SC light, reducing fluctuations by at least 90 percent. The seed wave also decreases the amount of energy needed to produce a supercontinuum by 25 percent.

This new-and-improved white light could help to push forward a range of technologies.

Solli and Bahram Jalali are developing time-stretching devices that slow down electrical signals; such devices could be used in new optical analog-to-digital converters 1,000 times faster than current electronic versions.

These converters could help to overcome the current conversion-rate bottleneck that holds back advanced radar and communication technologies.

Stabilized SC light could also be used to create super-fast cameras for laboratory use or incorporated into optical clockworks. (ANI)

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