Experimental Study on 0.5THz Superradiant Smith-Purcell Radiation

Summary form only given. Since it was first discovered, Smith-Purcell radiation (SPR) from electrons moving over a grating has been noted for its simple radiation mechanism and adopted for the generation of radiation which covers wide range of electromagnetic spectrum. These days´ growing interest in Terahertz frequency regime, 0.3-3 THz, and the lack of compact tunable sources in this spectral range are attracting more attention to SPR and various attempts have been made to improve the weak intensity of spontaneous Smith-Purcell radiation. Adopting quasi-optical Fabry-Perot cavity, backward wave interaction, pre-bunched electron beam, and photonic crystals are such examples. Recently, we´ve introduced another way of enhancing the Smith-Purcell radiation intensity by the use of counter-streaming electron beams and 1D slit array.