The HFML-FELIX free-electron laser facilities, FELIX, are co-funded by the UK Engineering and Physical Sciences Research Council (EPSRC) as a UK National Research Facility (NRF). This NRF aims to provide UK scientists with free access to FELIX, a unique ultrafast lightsource for mid-infrared and THz spectroscopy.

Unprecedented tuning range

FELIX offers unparalleled light characteristics unattainable with standard UK lab-scale equipment, making it essential for cutting-edge research. The combination of the specific wavelength range provided, the very short pulses, and the intensity are not available in other ways. For example, although shorter pulses or higher power are available elsewhere, they are not available in the mid- to far-infrared. Bench top systems can provide this spectral region, but not with these intensities or pulses. The source is accelerator-based, and therefore beyond reach for a regular university group, and a National Research Facility sharing model is ideal.

FELIX stands out globally, with only two other IR/THz FELs in Europe (CLIO in Paris, FELBE in Dresden) offering open access. It boasts the broadest tuning range, the most flexible pulse schemes, and the highest user beam hours. FELIX is also the only FEL facility featuring internationally developed beam lines, reinforcing UK collaboration and leadership in the field.FELIX differs significantly from UK-based facilities such as the Central Laser Facility (CLF) which offers different laser wavelengths and different regimes of pulse structure.

As the research landscape evolves, FELIX remains adaptive, shaping infrastructure roadmaps, expanding capabilities, and responding to emerging scientific needs. Its capabilities ensure UK researchers stay at the forefront of innovation.

Travel and subsistence support

Through this program, it is also possible to financially support UK-based groups for travel to the Netherlands and their accommodation costs (with a maximum of two visitors). Beam time applications are still required, and beam time is awarded based on a positive evaluation by the Program Advisory Council.