An XUV-FEL amplifier seeded using high-harmonic generation

20 Apr 2007

A team of scientists has designed a free-electron laser that will form part of the 4th Generation Light Source (4GLS) facility at Daresbury, UK (New J. Phys. 9 82).

The 4GLS project at the UK's Daresbury Laboratory will offer users a suite of high-brightness synchronized sources from terahertz frequencies into the extreme ultraviolet (XUV). In this design, researchers from the University of Strathclyde, the Daresbury Lab, the Rutherford Appleton Lab and Sheehy Scientific Consulting, propose a free-electron laser (FEL) amplifier operating in the XUV and seeded directly by a high-harmonic source.

The XUV-FEL, which will form part of the 4GLS facility, will generate photons with tunable energies from 8 to 100 eV at gigawatt peak power levels and will offer near Fourier-transform limited pulses of variable polarization.

4GLS must fulfill numerous criteria, and the researchers discuss some of the major design considerations and choices for the XUV-FEL. These include the design of the high-harmonic generation (HHG) seeding, the FEL amplifier and the synchronizing systems.

The researchers have also quantified the FEL output characteristics using numerical simulations. These results indicate that spatio-temporal synchronization between electron pulses and HHG seed is the most critical aspect to ensuring the success of the XUV-FEL design.