FELBE and TELBE, at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), are infrared and terahertz light sources driven by the superconducting ELBE electron accelerator — a rare combination of tunable free-electron lasers and a high-field terahertz source open to users.
At HZDR’s Center for High-Power Radiation Sources ELBE, two free-electron lasers known collectively as FELBE deliver coherent, intense, spectrally narrow and pulsed beams across the mid- and far-infrared. The radiation is continuously tunable from 5 to 250 micrometres, with picosecond to sub-picosecond pulses and energies of up to several microjoules. In addition, two TELBE beamlines provide high-power coherent terahertz radiation between 0.1 and 1.5 THz — superradiant pulses generated from the same accelerator. FELBE is among the few facilities of its kind in Europe to deliver a continuous pulse train at megahertz repetition rates.
At a glanceFacility profile
- Location
- Dresden, Germany
- Operator
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR)
- Type
- Infrared free-electron lasers (FELBE) and superradiant terahertz source (TELBE)
- Energy
- 40 MeV electron beam (superconducting ELBE accelerator)
- Spectral range
- 5–250 µm (FELBE); 0.1–1.5 THz (TELBE)
- Beamlines
- 2 FEL beamlines, plus TELBE terahertz beamlines
- Website
- hzdr.de/felbe
The scienceWhat researchers do here
Infrared and terahertz light is ideally suited to probing low-energy excitations in matter — lattice vibrations, spin waves, electronic transitions in semiconductors and quantum materials, and the collective dynamics that govern how materials respond to driving fields. The high repetition rate and tunability of FELBE make it powerful for time-resolved pump-probe spectroscopy, while TELBE’s intense terahertz pulses are used to drive and control matter directly. A distinctive capability is the combination of free-electron-laser light with pulsed magnetic fields of up to 70 tesla, opening experiments that few other laboratories can offer.
A laboratory for the low-energy world: FELBE and TELBE light up the vibrations, spins and slow electronic motions that ordinary lasers cannot reach.
Access for researchers
Calls for proposals are published twice a year, with awarded beam time scheduled in the following term. Access is quality-based and granted through peer review, in line with the European Charter for Access to Research Infrastructures.