Experimental Tests of the New Paradigm for Laser Filamentation in Gases

Abstract

Since their discovery in the mid-1990s, ultrafast laser filaments in gases have been described as products of a dynamic balance between Kerr self-focusing and defocusing by free electric charges that are generated via multi-photon ionization on the beam axis. This established paradigm has been recently challenged by a suggestion that the Kerr effect saturates and even changes sign at high intensity of light, and that this sign reversal, not free-charge defocusing, is the dominant mechanism responsible for the extended propagation of laser filaments. We report qualitative tests of the new theory based on electrical and optical measurements of plasma density in femtosecond laser filaments in air and argon. Our results consistently support the established paradigm.

4 pages, 4 figures

References in corpus (4)

• Ultrashort filaments of light in weakly-ionized, optically-transparent media
• Higher-order Kerr terms allow ionization-free filamentation in gases
• Direct measurement of the electron density of extended femtosecond laser pulse-induced filaments
• Temporal self-restoration of compressed optical filaments

Cited by in corpus (14)

• Optical nonlinearity in Ar and N${}_2$ near the ionization threshold
• On the Saturation of the Nonlinear Refractive Index in Atomic Gases
• Effect of a plasma grating on pump-probe experiments near the ionization threshold in gases
• Third and fifth harmonics generation by tightly focused femtosecond pulses at 2.2 μm wavelength in air
• Comparative investigation of third and fifth harmonic generation in atomic and molecular gases driven by mid-infrared ultrafast laser pulses
• From higher-order Kerr nonlinearities to quantitative modeling of 3rd and 5th harmonic generation in argon
• Higher-order Kerr effect and harmonic cascading in gases
• Memory effects in the long-wave infrared avalanche ionization of gases: A review of recent progress
• Higher-order Kerr improve quantitative modeling of laser filamentation
• Conical emission from laser filaments and higher-order Kerr effect in air
• Ultrasolitons: multistability and subcritical power threshold from higher-order Kerr terms
• On the interpretation of negative birefringence observed in strong-field optical pump-probe experiments: high-order Kerr and plasma grating effects
• Adiabatic Floquet model for the optical response in femtosecond filaments
• Modulational instability windows in the nonlinear Schrödinger equation involving higher-order Kerr responses