Abstract-Cherenkov terahertz surface plasmon excitation by an electron beam over an ultrathin metal film

Journal of Applied Physics

Pawan Kumar1,a), Rajeev Kumar2, and  Satish Kumar Rajouria
http://aip.scitation.org/doi/abs/10.1063/1.4971346
The mechanism of Cherenkov excitation of terahertz (THz) surface plasma wave (SPW), by a relativistic electron beam propagating over an ultrathin metal film deposited on glass,is investigated. The SPW field falls off exponentially in vacuum as well as glass, while the surface plasmon resonant frequency is lowered by the reduction of film thickness. The SPW field causes density bunching of the beam leading to current modulation and generation of THz radiation via the Cherenkov interaction. The frequency of the THz decreases with the energy of the beam, whereas the growth rate increases.