The X-rays we get in the hospital are limited by spatial resolution. They can't detect really small cancers because the X-ray source in your doctor's office is like a light bulb, not like a laser. If you had a bright, laser-like X-ray beam, you could image with far higher resolution. This system will impact medicine, biology and nanotechnology.
To generate laser-like X-ray beams, the team used a powerful laser to pluck an electron from an atom of argon, a highly stable chemical element, and then slam it back into the same atom. The boomerang action generates a weak, but directed beam of X-rays.
The obstacle they needed to hurdle was combining different X-ray waves emitted from a large number of atoms to generate an X-ray beam bright enough to be useful, according to Kapteyn. In other words, they needed to generate big enough waves flowing together to make a strong X-ray.
The researchers sent some weak pulses of visible laser light into the gas in the opposite direction of the laser beam generating the X-rays. The weak laser beam manipulates the electrons plucked from the argon atoms, whose emissions are out of sync with the main beam, and then slams them back into the atoms to generate X-rays at just the right time, intensifying the strength of the beam by over a hundred times.