Driven Radiation Of Ribbon Electron Beam As A Tool For Optical Modulation

The Cherenkov radiation and/or Smith-Purcell radiation, which are generated by electrons that move compactly along the surface of a slow-wave structure, can be modulated by deflecting of electron beam. When a resonant optical beam is incident, the structure functions as an amplifier. Swinging the electron beam through the interaction region modulates the gain and so the emitted optical intensity. One volt applied to simple upstream electrodes is sufficient to actuate the necessary deflection. Three schemes, involving either a dielectric transparent grating, metal reflective grating, or flat-layered dielectric structure, are considered as to their effectiveness in producing optical modulation. In principle, the rate of modulation can be 5% of the OB frequency (1000 Gbps for near infrared light). Feasibility of the concept can be tested in the THz spectral range by the modified Smith-Purcell type source