This newly created X-ray laser is just unimaginably powerful. It's a billion times brighter than any previous X-ray source, and it can probe hot dense matter at nearly four million degrees. This laser could unlock the secrets of the Sun.
Scientists at the US Department of Energy's SLAC National Accelerator Laboratory created the laser, which fires rapid-fire laser pulses to heat up matter to over 3.6 million degrees Fahrenheit and then probe what's going on inside. At those temperatures, matter turns into a special form known as solid plasma, which is only found inside the cores of stars and massive gas giants.
The laser, known as the Linac Coherent Light Source or LCLS, is the first of its kind able to actually penetrate inside solid matter thanks to the ultra-short wavelengths of its X-ray light. The SLAC scientists fired the laser at a piece of aluminum foil, which was flash-heated to create this special hot dense matter. The process only lasted a trillionth of a second, but the measurements taken by the LCLS in that time will greatly bolster existing theories and computer simulations on how solid plasma behaves. The endgame for these experiments could be recreating the nuclear fusion that powers the Sun.
The X-ray laser works just as conventional lasers do: by forcing electrons to move from higher energy levels to lower ones within atoms. In another experiment, the powerful X-ray pulses fired by LCLS dislodged electrons from the inner shells of some neon atoms in a capsule. As outer electrons fell in to fill these gaps, about 2% of the atoms emitted photons in the X-ray wavelengths. These new photons repeated the process, creating a domino effect that made the laser light 200 million times more powerful. In a statement, SLAC scientists explain how all this laser light could be put to use:
Although LCLS and the neon capsule are both lasers, they create light in different ways and emit light with different attributes. The LCLS passes high-energy electrons through alternating magnetic fields to trigger production of X-rays; its X-ray pulses are brighter and much more powerful. The atomic laser's pulses are only one-eighth as long and their color is much more pure, qualities that will enable it to illuminate and distinguish details of ultrafast reactions that had been impossible to see before. Researchers envision using both LCLS and atomic laser pulses in a synchronized one-two punch: The first laser triggers a change in a sample under study, and the second records with atomic-scale precision any changes that occurred within a few quadrillionths of a second.
Scientists had first predicted that X-ray lasers could be put to such use way back in 1967, but it's only now, 45 years later, that experimental science has caught up with the theory and made lasers like the LCLS possible. Now it's just a question of finding out what this laser can do. If these preliminary results are anything to go by, neither the most massive stars nor the tiniest atoms will be able to hide from its X-ray glare.
Via SLAC. Top photo courtesy University of Oxford/Sam Vinko. Illustration by Gregory M. Stewart, SLAC National Accelerator Laboratory.