FELIX logo

Location of Facility

Radboud University, Nijmegen, The Netherlands

Capabilities and services provided

The international free electron laser facility FELIX provides very bright, short pulsed, coherent light output, all the way from the mid-infrared to the microwave region of the spectrum. User access is provided to its infrared beam lines FLARE, FELIX-1 and FELIX-2 operating in the wavelength range 3-1500 µm and FELICE operating between 3-100 µm (layout see figure 1). The wavelength can be rapidly and continuously tuned over wide ranges without realignment (up to an octave, depending on configuration). The output of FELIX lasers consists of bursts of micropulses, each of which has controllable duration from a few tens of cycles to a few hundreds. The peak power can be very high, and the average power in the burst can also be very high (up to GW and kW respectively, depending on the wavelength). The temporal and transverse beam profile are close to transform and diffraction limited. Three of these beam lines are operated simultaneously and serve three user experiments in parallel.

The primary applications of the facility are found in areas benefitting either from the high brightness or the high fluence the FEL laser sources offer. Studies on saturation-relaxation phenomena e.g. applying techniques as pump-probe or photon-echo measurements make use of the high peak powers to investigate a variety of samples ranging from solid state to biological systems. Over the last decade, it has been demonstrated that the FELIX output has some unique features that make it highly suitable for IR-spectroscopy of (bio)molecules, complexes and clusters in the gas phase using various techniques summarized under 'action spectroscopy'.

The FLARE and FELIX beam lines are coupled to 12 advanced user laboratories in the fields of molecular and biomolecular spectroscopy (FTICR-MS, Ion Trap, cold 22-pole ion trap, He-droplet apparatus, laser ablation molecular beam setup), cluster sciences (molecular beam setup), time-resolved spectroscopy (pump-probe, transient grating, photon echo) and (femtosecond) laser spectroscopy. Moreover, it includes a unique combination by connecting to the magnets (up to 38 T DC field) of the High Field Magnet Laboratory Nijmegen (see figure 2). In addition, a lot of auxiliary equipment (e.g. synchronised table-top femtosecond lasers, ns-IR-OPOs, ns dye, Nd:YAG and excimer lasers, magnets, spectrometer, etc.) is available for experiments at the FELIX beam lines.

Contact for access


The FELIX Laboratory is a large-scale facility that is open for external users with projects selected by the Programme Advisory Committee. The facility issues 6-monthly calls for proposals, the deadlines being 15 May and 15 November.


FELIX Laboratory

Faculty of Science
Radboud University Nijmegen

Visiting address

Toernooiveld 7c
6525 ED Nijmegen
The Netherlands

Postal address

P.O. Box 9010
Internal postal box 74
6500 GL Nijmegen
The Netherlands

Research Areas aligned to facility

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