High-efficiency method and device, to produce coherent Smith-Purcell radiation

US8638824B2 · kind B2 · utility

Assignee

• COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES · FR

Inventors

• Jacques Gardelle · Pessac, FR
• John Donohue · Gradignan, FR

Key dates

• Filing date: Oct 2, 2012
• Grant date: Jan 28, 2014
• Expiry date: Oct 2, 2032

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01S2302/02
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

High-efficiency method and device, to produce coherent Smith-Purcell radiation. A conductive diffraction grating, delimited by two conductive walls, is used, and an electron beam is passed above the grating to generate the radiation. According to the invention, the speed of the electrons is sufficiently low in order that, in a diagram (wave number k, frequency f), the beam line (I) intersects a portion (V) of a branch of the dispersion relationship, located in the first Brillouin zone, and corresponding to the grating's fundamental mode, at a point (P) located outside the zone delimited by the light lines (III, IV), and the current density of the beam is sufficiently high to excite the grating's fundamental mode which is radiated towards the outside thereof.