FLASH, the Free-Electron LASer in Hamburg, started user operation in summer 2005 as the first free-electron laser for VUV and soft X-ray radiation. It is operated in the "self-amplified spontaneous emission" (SASE) mode and currently covers a wavelength range from 4.2 nm to about 45 nm in the first harmonic with GW peak power and pulse durations between 50 fs and 200 fs.  FLASH1 offers five beamlines for users in the 'Albert Einstein' hall (PG and BL beamlines). 

In the past years, an additional FEL undulator line in a separate tunnel - FLASH2-  and the new 'Kai Siegbahn' experimental hall have been built adjacent to the existing FLASH facility now called FLASH1. First lasing of FLASH2 was achieved in August 2014 in parallel to FLASH1. Now the FLASH facility at DESY comprises two separate and almost independent FEL sources. This upgrade enhances significantly the capacities for VUV and soft X-ray FEL users at DESY. Up to 6 beamlines (FL beamlines) will be offered in the 'Kai Siegbahn' hall starting in 2016.