The FLASH facility at the DESY research centre in Hamburg has established a new world record for the highest laser power at the shortest wavelengths.
The free-electron laser generated light flashes at wavelengths between 13.5 and 13.8 nanometres with an average power of 10 milliwatts and record energies of up to 170 microjoules per pulse. This is performed at repetition rates of 150 times per second.
Since the pulses have a duration of only around 10 femtoseconds, the peak power per pulse can reach 10 gigawatts. This level of power is greater than is can be generated at even the biggest plasma X-ray laser facilities worldwide. At 2.7 nanometres a specific part of the radiation, known as the fifth harmonic, enables FLASH to reach deep into the “water window”. This is a wavelength range that is important for the investigation of biological samples.
‘FLASH is currently the only laser facility in the world to deliver ultra-short high-power laser flashes in the X-ray range with a very high repetition rate,’ said DESY Research Director Professor Jochen R. Schneider.
‘FLASH opens up completely new experimental opportunities for researchers from nearly all the natural sciences, even within the water window between 2.3 and 4.4 nanometres. In this wavelength range, the carbon atoms in organic matter absorb radiation very well, whereas the water environment remains invisible. This enables investigations that have not been feasible so far, for instance single shot holographic imaging of cellular systems in their natural in vitro environments.’
The range around 13.5 nanometres is also critically important because laser radiation of this wavelength is required by the semiconductor industry to produce the next generation of microprocessors using EUV lithography.