THz generation by optical Cherenkov emission from ionizing two-color laser pulses

TL;DR

This paper investigates how two-color laser pulses generate broadband THz radiation through an optical Cherenkov effect, with simulations showing the emission angle depends on the front velocity of the current source exceeding the THz phase velocity.

Contribution

It reveals that the conical THz emission angle is governed by an optical Cherenkov effect, providing new insights into THz generation mechanisms from ionizing laser pulses.

Findings

The emission angle is determined by an optical Cherenkov effect.

The front velocity of the current source exceeds the THz phase velocity.

Simulation results match theoretical predictions.

Abstract

Two-color photoionization produces a cycle-averaged current driving broadband, conically emitted THz radiation. We investigate, through simulation, the processes determining the angle of conical emission. We find that the emission angle is determined by an optical Cherenkov effect, where the front velocity of the current source is faster than the THz phase velocity.