Circularly Polarized Component in the Smith–Purcell Radiation

We consider the polarization characteristics of the Smith—Purcell radiation (SPR) for a model grating consisting of oblique perfectly conducting strips separated by vacuum gaps, as well as for a “real” grating with a triangular period profile. It is shown that apart from linear polarization, SPR has a circularly polarized component. The results demonstrate the possibility of obtaining a monochromatic radiation source with the elliptic polarization in the terahertz wavelength range.