The most intense laser in the world will soon become twice as intense, thanks to a US$2 million upgrade from the National Science Foundation. The Hercules laser at the University of Michigan currently fires a beam with the power of 300 terawatts (TW), but by replacing certain outdated components that could be bumped up to a possible 1,000 TW. With that kind of power, the laser could lead to advances in astrophysics research and enable more precise, faster and cheaper medical x-rays.
Activated in 2007, the Hercules laser holds the Guinness World Record for Highest Intensity Focused Laser, creating a focused laser beam with an intensity of 20 sextillion watts per square centimeter. It has some stiff competition though: the Diocles laser at the University of Nebraska-Lincoln, for example, has a power of "only" 100 TW, but it pulses 100 times faster.
To keep Hercules ahead of the pack, the upgrade will bump its power up to 500 TW or even 1,000 TW, which should double or triple that record-holding intensity. That boost will be achieved by replacing three of the device's five ageing pump lasers – components that amplify ultrashort pulses of light. These were custom-built over 10 years ago, since that was the only way to reach a power of 300 TW, but nowadays, those are outstripped by commercially-available pump lasers.
So what can we learn by focusing a beam of light that's the equivalent of two or three times the amount of sunlight that hits the Earth onto a single grain of sand? The team says that a higher-powered Hercules could help shrink down particle accelerators to a "tabletop" size, rather than the several kilometers that facilities like CERN require. That could help more labs around the world probe the mysteries of astrophysics or the largely-untested field of quantum electrodynamics – the study of the quantum interactions between light and matter.
In more practical everyday applications, the x-rays produced by laser accelerators could eventually improve medical x-ray images. Rather than just highlighting dense materials like bone, high-energy x-ray beams will travel differently through different materials, allowing for more precise scans of soft tissues in the body. The team compares it to an MRI, only cheaper and with faster results.
"This upgrade enables a wide variety of different experiments," says Karl Krushelnick, director of the Center for Ultrafast Optical Science at the University of Michigan. "There are these exciting applications, and it also opens up a new regime at the very frontier of plasma physics, where quantum phenomena start to play an important role."
Source: University of Michigan
