Superradiant terahertz Smith-Purcell radiation from surface plasmon excited by counterstreaming electron beams

Young-Min Shin, Jin-Kyu So, Kyu-Ha Jang, Jong-Hyo Won, Anurag Srivastava, and Gun-Sik Park
School of Physics and Astronomy, National Research Laboratory for Micro and Nano Vacuum Electrophysics, Seoul National University, Seoul 151-747, Korea

(Received 4 September 2006; accepted 13 December 2006; published online 17 January 2007)
The authors show that evanescent tunneling transmission of effective surface plasmon polaritons between two counterstreaming electron beams noticeably increases Smith-Purcell radiation (SPR) intensity by about two orders of magnitude as well as lower its transition threshold from a spontaneous emission to a stimulated one. An emission mechanism of the superradiant SPR is theoretically analyzed by the dielectric conversion of the structured metal surface and the boundary matching condition of Maxwell's equations in comparison with numerical simulations. ©2007 American Institute of Physics
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