From lasers to high power X-rays would open new perspectives for scientists. They could, for example, help visualize atomic details of viruses or film chemical reactions live. But for pushing the current limits of X-ray lasers, the researchers must create a new technology. Sometimes you don’t need to reinvent the wheel. Instead of designing a new type of X-ray laser, researchers at SLAC looked instead a new way of using them. In particular, they have developed a new one optical laser pulse technique modern and very powerful.
This Stanford research institute is home to the most powerful X-ray laser on the planet, known as LCLS or Linac Coherent Light Source. Instead of inventing a new device, the SLAC team designed a system able to increase the strength of the existing laser. The method, called chirped pulse amplification, or CPA, allowed him to push the limits of the LCLS X-ray electron laser.
As a result, the center is now able to produce X-ray pulses ten times more powerful than before, without changing the LCLS infrastructure. The team published their findings in Physical review letters on November 18.
Chirped pulse amplification allowed the LCLS to operate at full power
Initially The LCLS acts as an atomic resolution camera. It takes snapshots of the smallest changes in molecules and materials in a tiny fraction of a second. The ultra-bright, ultra-fast X-ray pulses it produces are of great interest for many applications and for scientific research. However, increase its power making the timing of the laser pulses inconsistent and creates a distorted or inaccurate image.
To correct this problem, the researchers had to considerably reduce the laser power, which limits the possibilities. Because of these limitations, most researchers have used the X-ray source as a superfast flashlight, not an optical laser. Since the establishment of chirped heart rate boostcan the X-ray beam fully perform its function as an optical laser.
CPA technology creates ultra-powerful lasers
Haoyuan Li, postdoctoral fellow at SLAC and Stanford University claimed that current X-ray laser pulses from free-electron lasers have a peak power of only about 100 gigawatts. But with the amplification of chirped pulses into X-rays, his team was able to obtain both parameters of very powerful beam and a peak power of more than 1 terawatt. These ultra-powerful pulses took place for about 1 femtosecond.
CPA works by extending the duration of an energy pulse before going through an amplifier and then through a compressor that reverses the initial stage. The result is a super intense, clean and ultra short pulse. This technology has been invented in the 1980s by physicists Donna Strickland and Gérard Mourou. The latter has also received one The Nobel Prize in Physics in 2018 for these works. By perfecting this method, the researchers hope to be able to develop X-ray thrusters even more powerful than LCLS in the future.