Coupling nonlinear propagation with electronic Coulomb dynamics in two-color strong-field terahertz radiation
Phys. Rev. A 114, 043108 – Published 13 October, 2026
DOI: https://doi.org/10.1103/nhvj-tsk4
Abstract
Intense terahertz (THz) radiation has been a frontier focus for its broad applications in spectroscopy, imaging, and fundamental laser-matter interactions. We propose a method for characterizing THz generation from strong-field two-color laser interactions with gaseous media by explicitly coupling nonlinear propagation effects with microscopic Coulomb dynamics. The proposed approach shows significantly improved agreement with the experimental results compared to conventional models. It allows for a more precise and comprehensive analysis of the contributions of nonlinear propagation and Coulomb potentials to THz radiation, particularly in the phase-dependent terahertz polarization spectrum. The results provide key information for calibrating the relative phase of two-color laser fields, both in the input and at the plasma filamentation region, and connects the nonlinear modulation of THz polarization with macroscopic filamentation. Consequently, our method offers a more reliable foundation for probing strong-field ionization with THz radiation and for the optimized design of high-performance THz sources as well.
