First lasing of CAEP THZ free electron laser

First lasing of the CAEP THz FEL (CTFEL) facility was obtained in August 29, 2017. The facility consists of a GaAs photocathode high-voltage DC gun, a superconducting RF linac, a planar undulator and a quasi-concentric optical resonator. The central frequency of the first saturated lasing was 2.56 THz, with the spectral width about 1.9%. The average output power in the macro pulse was larger than 5.7 W.