High-Power Single-Cycle Terahertz Cherenkov Radiation Using a High-Charge Bunch to Drive Dielectric Prisms

Abstract

Terahertz (THz) pulses emission with a wide spectral band find broad applications in nowadays science and technology. However, the power and bandwidth of THz pulses generated by most of the available methods are not suitable. Aiming to generate a high-power and broadband THz pulse emission, in this article it is proposed to use a high-charge electron bunch to excite coherent Cherenkov radiation from a pair of dielectric prisms. Detailed theoretical analyses and simulation verifications on the temporal and spectral properties of Cherenkov radiation are performed. A 1–4-MeV electron gun, together with a buncher, is designed to generate an electron bunch with a bunch charge that exceeds several hundred picocoulombs while keeping its transversal dimension under 0.2 mm. A single-cycle THz pulse with spectral band covering the range from 0 to 1 THz can be realized via coherent Cherenkov radiation. The field intensity of THz pulse, which is proportional to the bunch charge, can reach tens of MV/m. This high-intensity and broadband THz pulse has potential applications in THz spectroscopy, THz imaging, and THz-driven particle accelerations.