Long-pulse, low-voltage infrared free-electron laser

Free-electron lasers (FEL´s) have been developed as powerful IR sources at several sites around the world. This paper considers the design of a relatively compact, low-cost, tunable IR FEL based on a 3-MeV electrostatic accelerator and a submillimeter-wavelength electromagnetic wiggler. The system should be sufficiently portable for use in the field, and applications such as remote sensing and industrial processing are envisioned. The wiggler is powered by a second-harmonic quasioptical gyrotron. A prescription for optimizing the gain of an electromagnetic wiggler FEL is derived and the nonlinear regime is treated by relating the electromagnetic wiggler FEL to the “universal” normalized FEL equations. A point design is given showing accelerator, gyrotron, and output parameters for a system capable of operating over the entire 3-13-μm wavelength atmospheric windows. A wide range of output characteristics is available