"That's the instantaneous intensity we can produce," said Karl Krushelnick, a physics and engineering professor. "I don't know of another place in the universe that would have this intensity of light. We believe this is a record."
The pulsed laser beam lasts just 30 femtoseconds. A femtosecond is a millionth of a billionth of a second.
Such intense beams could help scientists develop better proton and electron beams for radiation treatment of cancer, among other applications.
The record-setting beam measures 20 billion trillion watts per square centimeter. It contains 300 terawatts of power. That's 300 times the capacity of the entire U.S. electricity grid. The laser beam's power is concentrated to a 1.3-micron speck about 100th the diameter of a human hair. A human hair is about 100 microns wide.
This intensity is about two orders of magnitude higher than any other laser in the world can produce, said Victor Yanovsky, a research scientist in the U-M Department of Electrical Engineering and Computer Science who built the ultra-high power system over the past six years.
The laser can produce this intense beam once every 10 seconds, whereas other powerful lasers can take an hour to recharge.
"We can get such high power by putting a moderate amount of energy into a very, very short time period," Yanovsky said. "We're storing energy and releasing it in a microscopic fraction of a second."
To achieve this beam, the research team added another amplifier to the HERCULES laser system, which previously operated at 50 terawatts.
HERCULES is a titanium-sapphire laser that takes up several rooms at U-M's Center for Ultrafast Optical Science. Light fed into it bounces like a pinball off a series of mirrors and other optical elements. It gets stretched, energized, squeezed and focused along the way.
HERCULES uses the technique of chirped pulse amplification developed by U-M engineering professor emeritus Gerard Mourou in the 1980s. Chirped pulse amplification relies on grooved surfaces called diffraction gratings to stretch a very short duration laser pulse so that it lasts 50,000 times longer. This stretched pulse can then be amplified to much higher energy without damaging the optics in its path. After the beam is amplified to a higher energy by passing through titanium-sapphire crystals, an optical compressor reverses the stretching, squeezing the laser pulse until it's close to its original duration. The beam is then focused to ultra-high intensity.
In addition to medical uses, intense laser beams like these could help researchers explore new frontiers in science. At even more extreme intensities, laser beams could potentially "boil the vacuum," which scientists theorize would 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, "Ultra-high intensity 300-TW laser at 0.1 Hz repetition rate," is published online in the journal
Optics Express. The full text is available at
http://www.opticsinfobase.org/abstract.cfm?URI=oe-16-3-2109. Yanovsky and Krushelnick are authors of the paper.
Source: University of Michigan
Related stories:
Molecular motor works by detecting minute changes in force
Researchers at the University of Pennsylvania School of Medicine discovered that the activity of a specific family of nanometer-sized molecular motors called myosin-I is regulated by force. The motor puts tension on cellular springs that allow vibrations to be detected within the body. This finely tuned regulation has important implications for understanding a wide variety of basic cellular processes, including hearing and balance and glucose uptake in response to insulin. The findings appear in the most recent issue of
Science.
Physicists produce quantum-entangled images
Using a convenient and flexible method for creating twin light beams, researchers at the Joint Quantum Institute of the Commerce Department's National Institute of Standards and Technology and the University of Maryland have produced "quantum images," pairs of information-rich visual patterns whose features are "entangled," or inextricably linked by the laws of quantum physics. In addition to promising better detection of faint objects and improved amplification and positioning of light beams, the researchers' technique for producing quantum images—unprecedented in its simplicity, versatility, and efficiency—may someday be useful for storing patterns of data in quantum computers and transmitting large amounts of highly secure encrypted information. The research team, led by JQI's Paul Lett, describes the work in the June 12 edition of
Science Express.
Bright sparks make gains towards plastic lasers of the future
Imperial researchers have come one step closer to finding the 'holy grail' in the field of plastic semiconductors by demonstrating a class of material that could make electrically-driven plastic laser diodes a reality.
Engineers demonstrate first room-temperature semiconductor source of coherent Terahertz radiation
Engineers and applied physicists from Harvard University have demonstrated the first room-temperature electrically-pumped semiconductor source of coherent Terahertz (THz) radiation, also known as T-rays. The breakthrough in laser technology, based upon commercially available nanotechnology, has the potential to become a standard Terahertz source to support applications ranging from security screening to chemical sensing.
Rochester's Omega Laser Receives 50-Fold Power Increase to Become 'Petawatt' Laser
The University of Rochester will mark another important step in the effort toward attaining sustainable fusion, the ultimate source of clean energy, Friday, May 16.
Warming up for Magnetic Resonance Imaging
Standard magnetic resonance imaging, MRI, is a superb diagnostic tool but one that suffers from low sensitivity, requiring patients to remain motionless for long periods of time inside noisy, claustrophobic machines. A promising new MRI method, much faster, more selective — able to distinguish even among specific target molecules — and many thousands of times more sensitive, has now been developed in the laboratory by researchers at the Department of Energy's Lawrence Berkeley National Laboratory and the University of California at Berkeley.
New technique measures ultrashort laser pulses at focus
Lasers that emit ultrashort pulses of light are used for numerous applications including micromachining, microscopy, laser eye surgery, spectroscopy and controlling chemical reactions. But the quality of the results is limited by distortions caused by lenses and other optical components that are part of the experimental instrumentation.
Faster than a Speeding Bubble
What do melting chocolate and bubbles in a champagne glass have in common? Besides being treats one might sample at a sophisticated soiree, they are both handy examples of first-order phase transitions in which a material transforms from one phase to another—that is, atoms changing from an orderly arrangement into a more chaotic arrangement.
