A new far infrared free-electron laser

The operation of a new ultra compact diffraction grating coupled free-electron laser (FEL) has been demonstrated. The basic elements of the device which is termed a grating coupled oscillator (GCO) are the beam in a scanning electron microscope (SEM) and a diffraction grating which is mounted in the e-beam focal region of the SEM. The e-beam is controlled by the SEMʹs electron optical system and distributed feed back is provided by the grating itself. Recent experimental results are presented and techniques for extending the wavelength and power coverage are discussed.