Boosting terahertz-radiation power with two-color circularly polarized midinfrared laser pulses

TL;DR

This paper proposes a two-color circularly polarized mid-infrared laser scheme to significantly boost terahertz radiation energy and electric field strength emitted from atomic gases, supported by theoretical and simulation results.

Contribution

It introduces a novel two-color circularly polarized laser approach that enhances terahertz emission, combining strong-field approximation and particle-in-cell simulations.

Findings

Order-of-magnitude increase in terahertz energy

Significant enhancement of electric field amplitude

Supports recent experimental and numerical results

Abstract

A way to considerably enhance terahertz radiation, emitted in the interaction of intense mid-infrared laser pulses with atomic gases, in both the total energy and the electric-field amplitude is suggested. The scheme is based on the application of a two-color field consisting of a strong circularly polarized mid-infrared pulse with wavelengths of $1.6\div 4\,\mu{\rm m}$ and its linearly or circularly polarized second harmonic of lower intensity. By combining the strong-field approximation for the ionization of a single atom with particle-in-cell simulations of the collective dynamics of the generated plasma it is shown that the application of such two-color circularly polarized laser pulses may lead to an order-of-magnitude increase in the energy emitted in the terahertz frequency domain as well as in a considerable enhancement in the maximal electric field of the terahertz pulse. Our results support recently reported experimental and numerical findings.