A Mm-Wave Raman Free Electron Laser Experiment

Abstract

A new experiment has been constructed to study the Raman free-electron laser interaction at millimeter wavelengths. Preliminary measurements, conducted in a superradiant amplifier configuration, indicate the production of tens of MW's of power at approximately 3.5 mm (85 GHz), a wavelength consistent with a coupling of the slow-space-charge wave with the fundamental waveguide mode in the presence of the wiggler field. The radiation conversion efficiency is several percent, an order of magnitude improvement over previous experiments. The parametric dependence of power thresholds and wavelength on pump and guide magnetic fields are found to correlate with a small signal gain analysis of single particle trajectories.