title: Nature of spatiotemporal light bullets in bulk Kerr media.
abstract: We present a detailed experimental investigation which uncovers the nature of light bullets generated from self-focusing in a bulk dielectric medium with Kerr nonlinearity in the anomalous group velocity dispersion regime. By high dynamic range measurements of three-dimensional intensity profiles, we demonstrate that the light bullets consist of a sharply localized high-intensity core, which carries the self-compressed pulse and contains approximately 25% of the total energy, and a ring-shaped spatiotemporal periphery. Subdiffractive propagation along with dispersive broadening of the light bullets in free space after they exit the nonlinear medium indicate a strong space-time coupling within the bullet. This finding is confirmed by measurements of a spatiotemporal energy density flux that exhibits the same features as a stationary, polychromatic Bessel beam, thus highlighting the nature of the light bullets.
authors.affiliation: Department of Quantum Electronics, Vilnius University, Saulėtekio Avenue 9, Building 3, LT-10222 Vilnius, Lithuania.
authors.forename: D
authors.initials: D
authors.lastname: Majus
authors.affiliation: Department of Quantum Electronics, Vilnius University, Saulėtekio Avenue 9, Building 3, LT-10222 Vilnius, Lithuania.
authors.forename: G
authors.initials: G
authors.lastname: Tamošauskas
authors.affiliation: Department of Quantum Electronics, Vilnius University, Saulėtekio Avenue 9, Building 3, LT-10222 Vilnius, Lithuania.
authors.forename: I
authors.initials: I
authors.lastname: Gražulevičiūtė
authors.affiliation: Department of Quantum Electronics, Vilnius University, Saulėtekio Avenue 9, Building 3, LT-10222 Vilnius, Lithuania.
authors.forename: N
authors.initials: N
authors.lastname: Garejev
authors.affiliation: Dipartimento di Scienza e Alta Tecnologia, Università degli Studi dell'Insubria, Via Valleggio 11, I-22100 Como, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Lotti
authors.affiliation: Centre de Physique Théorique, CNRS, Ecole Polytechnique, F-91128 Palaiseau, France.
authors.forename: A
authors.initials: A
authors.lastname: Couairon
authors.affiliation: School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14-4AS, United Kingdom.
authors.forename: D
authors.initials: D
authors.lastname: Faccio
authors.affiliation: Department of Quantum Electronics, Vilnius University, Saulėtekio Avenue 9, Building 3, LT-10222 Vilnius, Lithuania.
authors.forename: A
authors.initials: A
authors.lastname: Dubietis