First light from the SwissFEL Experimental Laser

The experimental laser is an important component for performing time resolved optical pump - X-ray probe experiments at SwissFEL. Only a very high reliability and reproducibility guarantees successful experiments. Flexibility in wavelength is achieved by subsequent optical parametric amplification of the laser output.

In a synergy between different research groups at PSI, the SwissFEL Experimental Laser 1 is successfully delivered and installed in a temporary Laser lab by Coherent. At the end of 2016 the system will be moved to its final destination in the SWISSFEL building. There the experimental lasers will be part of the new SwissFEL facility, they will be located at the end of the accelerator tunnel on top of experimental stations A and B, in a dedicated laser hutch (LHx). The system consists of 4 next generation diode pumped, intracavity doubled Nd:YLF lasers (REVOLUTION), a Ti:Sapphire oscillator (VITARA) and a regenerative amplifier (Legend USX) in combination with additional amplification stages. After installation in the temporary lab, the oscillator started to mode-lock directly out of the box. The 800 nm laser output at 100 Hz repetition rate after the pulse amplification was measured to > 20 mJ, with a sub 30 fs pulse duration (SPIDER measurement after pulse compression).

The main amplifier specs were already successfully demonstrated during the installation. Verification of parameters depending on long term drifts and stabilities that strongly depend on the building environment will be tested after final installation in the SwissFEL building. Due to the pre-installation in the temporary laser lab, it is possible to become acquainted with the system, to setup a full monitoring and diagnostics system and eventually to debug potential problems in the next months before final installation.