Pump beams synchronized with the main photon beams (HHG or PXS) are a critical part of the ELI-Beamlines facility, as many users‘ experiments require two synchronized beams. Advanced pump-probe schemes will be provided in the E1 hall with either a pump beam and a main beam (HHG or PXS) or synchronized HHG and PXS beams. Beams from the optical probes end-station will also be synchronized with other beams. There will be flexibility in the configuration and the ability to use various combinations of pump beams and the main beam at different experimental locations.
Planned pump beams in E1:
The optical parametric amplifier, pumped by 10 mJ pulses split from the L1 laser, will produce pulses with wavelengths in the range of 260–2,600 nm, pulse duration around 40 fs and energy per pulse <3 mJ in the wavelengths range of 800–2600 nm, and <300 microJ in the range of 260–750 nm. OPA beams can be used in all end-stations (both HHG and PXS beam lines).
Few-cycle pulses with durations of <7 fs and energies around 0.5 mJ will be produced by a hollow fiber pulse compressor, pumped by 1–2 mJ pulses split from the L1 laser. Few-cycle beams will be used primarily at the MAC end-station at direct HHG beam lines for AMO experiments, where ultrashort pulse duration is most likely to be required.
Direct auxiliary beam (high power)
The direct beam (without OPA) with energy per pulse up to 4 mJ and pulse duration down to 20 fs will be available for experiments that require high intensity pump beam. This beam can be focused to intensity on the order of 1016 Wcm-2.
A laser-driven THz source will be developed in collaboration with Maria Krikunova, a junior professor at Technical University Berlin (TUB). The system consists of three modules:
- A THz generation path based on optical rectification in a nonlinear crystal
- A THz diagnostic using electro-optic sampling (EOS)
- A timing tool for compensation of residual temporal jitter due to the long laser distribution path (the need for this will be investigated).
This instrument will serve a dual purpose: it will be used for THz streaking experiments to study electron dynamics on the 5–250 fs time scale. Furthermore, it will be used to pump low energy collective excitations directly in molecules, nanoparticles, and solid-state samples and to follow the induced structural changes in pump-probe experiments using optical, VUV, and X-ray imaging and spectroscopy techniques.