Stimulated coherent Smith-Purcell radiation from a metallic grating

• Published in: IEEE journal of quantum electronics 1999-10, Vol.35 (10), p.1386-1389
• Main Authors: Chuan Sheng Liu, Tripathi, V.K.
• Format: Article
• Language: English
• Subjects: Arrayed waveguide gratings; Arrays; Beam currents; Beams (radiation); Cherenkov radiation; Current measurement; Electromagnetic measurements; Electromagnetic waveguides; Electromagnetism; electron and ion optics; Electron beams; Exact sciences and technology; Excitation; Fundamental areas of phenomenology (including applications); Goniometers; Instability; Periodic structures; Phase measurement; Phased arrays; Physics; Radiation by moving charges; Thresholds; Wavelength measurement; Wavelengths; Wavenumber
• ISSN: 0018-9197; 1558-1713
• DOI: 10.1109/3.792548

A relativistic electron beam with velocity /spl nu//sub b/z passing over a metallic grating, with deep periodic depressions of wavenumber k/sub 0/z, excites a slow wave (/spl omega/, k/sub z/) via Cerenkov interaction, /spl omega/=(k/sub z/+k/sub 0/)/spl nu//sub b/. The beam bunches induce currents in the fins of the grating that act as a phased radiating dipole array, thereby generating coherent radiation at a wavelength /spl lambda/=(2/spl pi//k/sub 0/l)(c//spl nu//sub b/-sin/spl theta/) where l is an integer and /spl theta/ is the angle of emission measured from the normal of the grating. The current threshold for the instability and radiation power scaling with beam current are discussed.