Mesa+, Enschede
The photonic free-electron laser (pFEL) aims to realize a compact TeraHertz source that emits Watt-level and tuneable radiation. For this purpose it uses a photonic structure, which coherently couples the Cerenkov radiation from a set of individual electron beams streaming through this structure. The resulting transverse coherence of the radiation allows a power scaling of the device by extending its cross-section and the number of electron beams. To study the fundamental physics of such devices, and to compare single beam with multi-beam performance, we first designed a single electron beam pFEL operating at a low frequency of around 22 GHz. Choosing such low operating frequency facilitates pumping of the pFEL by a single electron beam. This electron beam possesses a relatively high current of 2 A and its acceleration voltage is tuneable between 7 kV and 15 kV. It is guided by a solenoid through a metal photonic structure of 30 cm length. The general design of the single beam pFEL will be presented.
SAIC, McLean
JLAB, Newport News, Virginia
Mesa+, Enschede
We describe a procedure for the simulation of free-electron laser oscillators. The simulation uses a combination of the MEDUSA simulation code for the FEL and the OPC code to model the resonator. The simulations are compared with recent observations of the oscillator at the Thomas Jefferson National Accelerator Facility and are in substantial agreement with the experiment.
JLAB, Newport News, Virginia
ATF, Boulder
Twente University, Laser Physics and Non-Linear Optics Group, Enschede
We report the design, and broadly tunable operation, for the first time, of a high average power free-electron laser using edge-outcoupling. Using the FEL in this configuration, we achieved a maximum stable output power of 270W at 2.53 μm, and could tune with an output of 20 W or higher from 0.8 to 4.2 μm. The output was in the form of a continuous train of sub-ps pulses at 4.68 MHz. Measurements of gain, loss, and the output mode are compared with models.