KILOWATT LASING IN A FREE-ELECTRON LASER

A Free Electron Laser (FEL) called the IR Demo is operational as a user facility at Thomas Jefferson National Accelerator Facility in Newport News, Virginia, USA. It utilizes a 48 MeV superconducting accelerator that not only accelerates the beam but also recovers about 80% of the electron-beam power that remains after the FEL interaction. Utilizing this recirculation loop the machine has recovered cw average currents up to 5 mA, and has lased cw with up to 1720 W output at 3.1 microns. It is capable of output wavelengths in the 2 to 6 micron range and can produce ~0.7 ps pulses in a continuous train at ~75 MHz. This pulse length has been shown to be nearly optimal for deposition of energy in materials at the surface. Upgrades in the near future will extend operation beyond 10 kW average power in the near IR and kilowatt levels of power at wavelengths from 0.3 to 30 microns. This paper will cover the performance measurements of this groundbreaking laser and present an overview of the applications tests underway.