Refractive Index Modification Induced by Femtosecond Laser Filament

Sagar Pokharel, Arthur Dogariu, Richard Miles, Albina Tropina

Research output: Chapter in Book/Report/Conference proceedingConference contribution


A self-consistent, multi-dimensional three-temperature plasma model for laser-induced nonequilibrium plasma is integrated with a semi-classical model for refractive index calculations to explore refractive index modifications in femtosecond laser-induced filaments. The investigation focuses on single filaments in nitrogen at atmospheric pressure, presenting a detailed analysis of the spatiotemporal evolution of the refractive index field during the filament’s decay. The fast temporal evolution in the refractive index at early times results from the exponential decay nature of electron density. Equally important factors include the dissociation and vibrational excitation of molecular nitrogen. A comprehensive analysis of the relative contributions to the refractive index among different components depends on the initial electron density, dissociation fraction, electron temperature, and the relaxation of electron energy to vibrational states. A thorough analysis is presented, spanning a range of plasma parameters, providing a quantitative understanding of the impact of thermodynamic nonequilibrium, dissociation, and hydrodynamic effects.

Original languageEnglish (US)
Title of host publicationAIAA SciTech Forum and Exposition, 2024
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
ISBN (Print)9781624107115
StatePublished - 2024
EventAIAA SciTech Forum and Exposition, 2024 - Orlando, United States
Duration: Jan 8 2024Jan 12 2024

Publication series

NameAIAA SciTech Forum and Exposition, 2024


ConferenceAIAA SciTech Forum and Exposition, 2024
Country/TerritoryUnited States

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering


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