Free—electron lasers were invented by John Madey in 1976 at Stanford University. The work builds on research done by Hans Motz and his coworkers who made the first undulator at Stanford in 1953 using the wiggler magnetic configuration which is at the heart of a free-electron laser. Madey used a 24 MeV electron beam and 5 m long wiggler to amplify a signal. Soon afterward, other laboratories with accelerators started developing such lasers.