Vacuum Ultraviolet is a rare color of laser light developed for the very first time at the DOE's Thomas Jefferson National Accelerator Facility.
The color is absorbed by air molecules, which is why it's created in a vacuum.
The light, which is 100 times brighter than other laser lights, could lead to a new method for determining the age of ancient materials between 100,000 and 1 million years. For example, the polar ice cap. Carbon dating caps out at around 62,000 years.
Jefferson researchers produced vacuum ultraviolet with a free-electron laser. It works by shooting an electron beam into a magnetic vacuum tube that accelerates the electrons to near-light speeds before sending them through a “wiggler.” The wiggler is another tube, with alternating magnets that cause the electrons to bounce around. In the process they give off some photons, which get directed towards a mirror.
The mirror is tilted so that a few of the photons bounce back into the wiggler and excite the electrons even more, resulting in more emitted photons. The other photons are directed elsewhere. Eventually, the iterative process builds up a large enough stream of photons that they reach a high-energy steady state: a laser. The final color is controlled by either sending more power via the electron beam or adjusting the distance between the wiggler and the mirror.
Scientists say that they hope to be ready to trial some applications with the new laser light by March.
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