Year: 2025
Type: article
Abstract: Harmonic generation in underdense spatially homogeneous plasma is generally expected to be inefficient: in an unmagnetized uniform plasma the fundamental and its harmonics cannot be phase matched, resulting in third-harmonic generation efficiencies of no more than ${10}^{\ensuremath{-}5}$. Here, we describe how a strong uniform magnetic field allows phase-matched harmonic generation in constant-density plasma. We derive phase-matching relations for type-I and type-II second-, third-, and fourth-harmonic generation, and confirm these relations with particle-in-cell simulations. These simulations show that for weakly relativistic femtosecond pulses the efficiencies of second-, third-, and fourth-harmonic generation can reach at least 70%, 14%, and 2%, respectively. Additionally, if driven by a two-color beam, third-harmonic generation is found to be over 70% efficient and fourth-harmonic generation is found to be over 30% efficient.
Source: Physical Review Applied
DOI: 10.1103/6qnr-tm78
Authors: Sida Cao, Matthew R. Edwards
Institution: Stanford University
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4417268174