Scientists from the University of Michigan claim to have created the world's most powerful laser.

The Hercules device pumps out 20 billion trillion watts per square centimetre, equivalent to taking all the light that falls on the Earth from the Sun and focusing it to a point the size of a grain of sand.

"That is the instantaneous intensity we can produce," said Karl Krushelnick, a physics and engineering professor at the University of Michigan.

"I do not know of another place in the universe that would have this intensity of light. We believe this is a record."

The beam can stay on for just 30 femtoseconds, around 30 million billionths of a second, but an innovative design means that the laser takes only 10 minutes to recharge before being able to fire again. Traditional lasers would take over an hour.

"We can get such high power by putting a moderate amount of energy into a very, very short time period," said Victor Yanovsky, a research scientist in the Department of Electrical Engineering and Computer Science at Michigan.

"We are storing energy and releasing it in a microscopic fraction of a second."

The titanium-sapphire laser took six years to build and takes up several rooms at the university's Center for Ultrafast Optical Science. The team hopes that it can be used for medical treatments and to harness fusion reactions.

A scientific paper on the research, entitled 'Ultra-high intensity 300-TW laser at 0.1 Hz repetition rate', is available on the OpticsInfoBase website.