Porträt Prof. Dr. Helm, Manfred; FWI

Prof. Dr. Manfred Helm
Phone: +49 351 260 - 2260
Fax: +49 351 260 - 3285

Free-Electron Lasers at the ELBE - Center for High-Power Radiation Sources at the HZDR in Dresden-Rossendorf

FELBE is an acronym for the free-electron laser (FEL) at the Electron Linear accelerator with high Brilliance and Low Emittance (ELBE) located at the Forschungszentrum Dresden-Rossendorf, Germany. The heart of ELBE is a superconducting linear accelerator operating in cw mode with a pulse repetition rate of 13 MHz. The acceleration is performed in two superconducting units with 20 MV each. The average beam current is 1 mA. The electron beam is guided to several laboratories where secondary beams (particle and electromagnetic) are generated (→ details). Two free-electron lasers (U37-FEL and U100-FEL), produce coherent electromagnetic radiation in the mid and far infrared (4 - 250 µm). Pulse energies are in the few 100 nJ range with pulse duration of a few  picoseconds. The typical operation mode offers 13 MHz micropulse repetition rate, in macropulses of a few 100 μs at up to 25 Hz or, alternatively,  FEL operation in a continuous 13 MHz mode.

The two free-electron lasers U37-FEL and U100-FEL with the undulators, U37 and U100, produce intense, coherent infrared radiation, which is tunable over a wide wavelength range by changing the electron energy or the undulator magnetic field.
(→ FEL description, → FELs worldwide)


Parameters of the FEL radiation


  5 -   40 µm

18 - 250 μm

U37-FEL with undulator U37 (as of summer 2017)

U100-FEL with undulator U100

Pulse energy 0.01 - 2 μJ depending on wavelength
Pulse length 1 - 25 ps depending on wavelength
Repetition rate 13 MHz 3 modes:
  • cw
  • macropulsed > 100 μs, < 25 Hz
  • single-pulse switched at kHz/Hz

As a user facility FELBE is open for external users.

Please see the ELBE user site for further information


CALIPSOplus is the network of accelerator-based lightsources (synchrotrons and FELs) in Europe and shall be funded from the European framework programme for Research and Innovation Horizon 2020 as "Integrating Activity". If the Grant Agreement will be signed as expected the project will start on May 1st, 2017, coordinated by HZDR. In the framework of the Trans-national Access programme user groups from outside Germany requesting access to FELBE  will then be able to apply for a reimbursement of their travel costs. Please visit the dedicated site on Trans-national Access to ELBE for more detailed information.

FELs of Europe LogoFELBE is a member of FELs OF EUROPE, "a collaboration of all free electron laser (FEL) facilities in Europe, with the goal to meet the technological and scientific challenges of these novel and rapidly developing technologies and to provide a worldwide unique, pan-European research infrastructure that enables exploiting the full scientific potential of these unique accelerator based short-pulse lightsources."
(see mission statement )

 Here is more information about

The infrared radiation is guided to a diagnostic station first and then delivered to six user laboratories. In some of the labs there are table-top femtosecond lasers, which are synchronized to the FEL pulses, thus providing the possibility of multi-color pump-probe experiments.

Here is more information about

as well as

Since 2007 the FELs are connected with the pulsed high-magnetic field laboratory.