Cavity dumping of an injection-locked free-electron laser

This letter reports cavity dumping of an electrostatic-accelerator-driven free-electron laser (FEL), while it is injection-locked to a frequency-stabilized 240 GHz solid-state source. Cavity dumping enhances the FEL output power by a factor of ∼8, and abruptly cuts off the end of the FEL pulse. The cavity-dumped, injection-locked FEL output is used in a 240 GHz pulsed electron spin resonance experiment.