# Generation of High-Power, Tunable Terahertz Radiation from Laser Interaction with a Relativistic Electron Beam

## TL;DR

This paper introduces a laser-based method to generate high-power, tunable terahertz radiation by inducing density bunching in relativistic electron beams, enabling efficient THz source development.

## Contribution

It presents a novel slice energy spread modulation technique using laser pulses to produce high-quality, tunable THz radiation with preserved beam integrity.

## Key findings

- Achieves 1-10 THz tunable radiation with high power
- Demonstrates effective density bunching via laser-induced slice energy spread modulation
- Maintains beam quality suitable for advanced applications

## Abstract

We propose a method based on the slice energy spread modulation to generate strong subpicoseond density bunching in high-intensity relativistic electron beams. A laser pulse with periodic intensity envelope is used to modulate the slice energy spread of the electron beam, which can then be converted into density modulation after a dispersive section. It is found that the double-horn slice energy distribution of the electron beam induced by the laser modulation is very effective to increase the density bunching. Since the modulation is performed on a relativistic electron beam, the process does not suffer from strong space charge force or coupling between phase spaces, so that it is straightforward to preserve the beam quality for further applications, such as terahertz (THz) radiation and resonant excitation of plasma wakefield. We show in both theory and simulations that the tunable radiation from the beam can cover the frequency range of 1-10 THz with high power and narrow-band spectra.