Frequency-domain calculation of Smith-Purcell radiation for metallic and dielectric gratings

TL;DR

This paper compares Smith-Purcell radiation from metallic and dielectric gratings using frequency-domain simulations, revealing efficiency differences and resonance effects in the radiation intensity.

Contribution

It introduces a frequency-domain simulation model for Smith-Purcell radiation and compares metallic and dielectric gratings, highlighting efficiency and resonance phenomena.

Findings

Dielectric gratings are less efficient than metallic ones for 30 keV electrons.

Radiation intensity oscillates with grating tooth height due to electromagnetic resonances.

3D and 2D models show consistent results, validating the simulation approach.

Abstract

The intensity of Smith-Purcell radiation from metallic and dielectric gratings (silicon, silica) is compared in a frequency-domain simulation. The numerical model is discussed and verified with the Frank-Tamm formula for Cherenkov radiation. For 30 keV electrons, rectangular dielectric gratings are less efficient than their metallic counterpart, by an order of magnitude for silicon, and two orders of magnitude for silica. For all gratings studied, radiation intensity oscillates with grating tooth height due to electromagnetic resonances in the grating. 3D and 2D numerical models are compared.