X-ray lasers from tabletop device

June8 2012 from bbc

An international team of scientists has generated the first laser-like beams of X-rays from a tabletop device.

Most of today's X-ray lasers require so much power they rely on facilities the size of sports stadiums.

This has prompted efforts to build a cost-effective and reasonably sized X-ray laser.

The development, reported in Science journal, could pave the way for super high-resolution imaging that could peer into a cell or a chemical reaction.

"Because X-ray wavelengths are 1,000 times shorter than visible light and they penetrate materials, these coherent X-ray beams promise revolutionary new capabilities," said co-author Margaret Murnane, professor of physics at the University of Colorado in Boulder, US.

In a laser beam, all the photons (light particles) oscillate in perfect unison. The wave crests are aligned - this kind of radiation is called "coherent".

The energy for the X-ray beam was supplied by short infrared laser pulses. They are fired at noble gases, where they rip electrons out of the atoms.

These electrons are then accelerated by the infrared light and return to their atoms, where they convert their kinetic energy into X-ray radiation.

The coherent beam generated in the latest study covers a broad energy spectrum - simultaneously streaming ultraviolet light, X-rays, and all wavelengths in between.

"This is the broadest spectral bandwidth, coherent light source ever generated," said Prod Henry Kapteyn, from the University of Colorado at Boulder.

The kind of radiation produced used to be available only in expensive particle accelerators called synchrotrons.

"Synchrotrons still deliver more photons per second than our beam does, but for many applications, our light source will be very useful," said co-author Audrius Pugzlys of the Technical University, Vienna in Austria.