Pulsed Mid-infrared Radiation from Spectral Broadening in Laser Wakefield Simulations

TL;DR

This paper investigates how high power laser pulses propagating through plasma can generate mid-infrared radiation via spectral red-shifting, with a focus on the dependence on pulse and plasma parameters.

Contribution

It provides simulation-based analysis of the parametric dependence of MIR generation in laser wakefield interactions, highlighting the mechanisms of spectral shifting and pulse depletion.

Findings

Spectral red-shifting occurs during laser pulse propagation in plasma.

MIR generation depends on pulse energy, duration, and plasma density.

Energy depletion correlates with spectral red-shift and pulse action conservation.

Abstract

Spectral red-shifting of high power laser pulses propagating through underdense plasma can be a source of ultrashort mid-infrared (MIR) radiation. During propagation, a high power laser pulse drives large amplitude plasma waves, depleting the pulse energy. At the same time, the large amplitude plasma wave provides a dynamic dielectric response that leads to spectral shifting. The loss of laser pulse energy and the approximate conservation of laser pulse action imply that spectral red-shifts accompany the depletion. In this paper, we investigate, through simulation, the parametric dependence of MIR generation on pulse energy, initial pulse duration, and plasma density.