Washington, February 16 : Scientists at the University of Michigan say that they have devised a way to produce a laser beam about as intense as a concentrated ray of the entire sunlight shining towards Earth would be if it were focussed onto one grain of sand.
"That's the instantaneous intensity we can produce. I don't know of another place in the universe that would have this intensity of light. We believe this is a record," said Karl Krushelnick, a physics and engineering professor.
The pulsed laser beam lasts just 30 femtoseconds (a millionth of a billionth of a second).
The Michigan team believes that such intense lasers may be helpful in developing better proton and electron beams for radiation treatment of cancer, among other applications.
The record-setting beam measures 20 billion trillion watts per square centimetre. It contains 300 terawatts of power, 300 times the capacity of the entire US electricity grid. Its power is concentrated to a 1.3-micron speck, about 100th the diameter of a human hair.
Victor Yanovsky, who built the ultra-high power system over the past six years, says that this intensity is about two orders of magnitude higher than any other laser in the world can produce.
As compared to other powerful lasers that take about an hour to recharge, the new laser can produce the intense beam once every 10 seconds.
"We can get such high power by putting a moderate amount of energy into a very, very short time period. We're storing energy and releasing it in a microscopic fraction of a second," said Yanovsky, a research scientist in the U-M Department of Electrical Engineering and Computer Science.
To produce such an intense beam, the researchers added another amplifier to the HERCULES laser system, which previously operated at 50 terawatts.
HERCULES is a titanium-sapphire laser at the university's Center for Ultrafast Optical Science. Light fed into it bounces like a pinball off a series of mirrors and other optical elements, and gets stretched, energized, squeezed and focused along the way.
Besides showing some promise of better medical applications in future, the intense laser beam may also help researchers explore new frontiers in science.
The scientists believe that at even more extreme intensities, laser beams could potentially "boil the vacuum", which may generate matter by merely focusing light into empty space.
Some scientists also see applications in inertial confinement fusion research, coaxing low-mass atoms to join together into heavier ones, and release energy in the process.
A paper on this research has been published online in the journal Optics Express.