The Polish free electron laser (POLFEL), will provide tunable coherent electromagnetic radiation in the range from several nanometers (Soft X rays, SX) to several hundred micrometers (Terahertz radiation, THz). The radiation of free electron lasers (FEL) is emitted in impulses, which last from a few femtoseconds for SX to tens of picoseconds for the THz range, with peak power of the order of 1 GW over the whole range of the frequency spectrum. As one of the few free electron lasers, the proposed source will be able to switch to the emission of high average power of the order of several tens of watts over its entire operating range. For the most part of this range it will be one of the most powerful sources of coherent radiation. POLFEL will complement the capabilities of conventional lasers by extending the available spectrum and will provide transverse and longitudinal coherent light, which is impossible for synchrotrons. It will also provide higher intensity by several orders of size and magnitude and pulse durations from 10 to 10 000 times faster than existing sources.

POLFEL will consist of three parts: the electron accelerator, an undulator (where the scattered electrons emit radiation), and the experimental stations. POLFEL’s linear accelerator will employ the TESLA technology, which was used in the FLASH laser accelerator and is currently being used in the construction of the European X-FEL, and is planned for the future lepton collider for particle physics, ILC. Undulators which can produce light with variable linear polarization plane and direction of the axis of elliptical polarization will be installed in POLFEL. Achieving the planned wavelength range requires the construction of an accelerator which is capable of giving electrons an energy of several hundred mega electron volts, the associated undulators and several experimental systems designed to operate in the appropriate ranges of wavelength will be required to exploit the experimental possibilities fully.

The construction of POLFEL will be divided into two stages. In the first stage, a source will be created, capable of emitting radiation in the range from the infrared to terahertz wavelengths. It willbe equipped with an accelerator with a final energy of 50 MeV, two undulators and an experimental line. The first stage of this project will discover new optimizations which will be used in further phases. A possible development will be to perform experiments exploiting the unique capabilities of the NCBJ center in Swierk by creating a laboratory that uses both FEL photon beams and neutrons produced in the MARIA nuclear reactor.

POLFEL beamlines will be open to users from both Poland and abroad.