FLASH at DESY in Hamburg, the first and currently only free-electron laser for VUV and soft X-ray radiation, has started user operation in summer 2005. Currently it covers a wavelength range from 13 nm to 50 nm with GW peak power and pulse durations between 10 fs and 50 fs. Approximately 20 weeks of beamtime are provided per year for scientific experiments that are not possible on any other radiation source.
Currently there are four beamlines (PG2, BL1, BL2, BL3) in operation and a fifth beamline (PG1) is under construction. An additional optical laser system is provided for pump-probe experiments. It is fully synchronized with the FEL beam.