title: Tubular filamentation for laser material processing.
abstract: An open challenge in the important field of femtosecond laser material processing is the controlled internal structuring of dielectric materials. Although the availability of high energy high repetition rate femtosecond lasers has led to many advances in this field, writing structures within transparent dielectrics at intensities exceeding 10(13) W/cm(2) has remained difficult as it is associated with significant nonlinear spatial distortion. This letter reports the existence of a new propagation regime for femtosecond pulses at high power that overcomes this challenge, associated with the generation of a hollow uniform and intense light tube that remains propagation invariant even at intensities associated with dense plasma formation. This regime is seeded from higher order nondiffracting Bessel beams, which carry an optical vortex charge. Numerical simulations are quantitatively confirmed by experiments where a novel experimental approach allows direct imaging of the 3D fluence distribution within transparent solids. We also analyze the transitions to other propagation regimes in near and far fields. We demonstrate how the generation of plasma in this tubular geometry can lead to applications in ultrafast laser material processing in terms of single shot index writing, and discuss how it opens important perspectives for material compression and filamentation guiding in atmosphere.
authors.affiliation: Département d'Optique P. M. Duffieux, Institut FEMTO-ST, UMR 6174 CNRS Université de Franche-Comté, F-25030 Besançon cedex, France.
authors.forename: Chen
authors.initials: C
authors.lastname: Xie
authors.affiliation: 1] Centre de Physique Théorique, CNRS, Ecole Polytechnique, F-91128 Palaiseau, France [2] Laboratoire Hubert Curien, UMR CNRS 5516, Université de Lyon, Université Jean Monnet, F-42000 Saint-Etienne, France.
authors.forename: Vytautas
authors.initials: V
authors.lastname: Jukna
authors.affiliation: Centre de Physique Théorique, CNRS, Ecole Polytechnique, F-91128 Palaiseau, France.
authors.forename: Carles
authors.initials: C
authors.lastname: Milián
authors.affiliation: Département d'Optique P. M. Duffieux, Institut FEMTO-ST, UMR 6174 CNRS Université de Franche-Comté, F-25030 Besançon cedex, France.
authors.forename: Remo
authors.initials: R
authors.lastname: Giust
authors.affiliation: Département d'Optique P. M. Duffieux, Institut FEMTO-ST, UMR 6174 CNRS Université de Franche-Comté, F-25030 Besançon cedex, France.
authors.forename: Ismail
authors.initials: I
authors.lastname: Ouadghiri-Idrissi
authors.affiliation: Laboratoire Hubert Curien, UMR CNRS 5516, Université de Lyon, Université Jean Monnet, F-42000 Saint-Etienne, France.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Itina
authors.affiliation: Département d'Optique P. M. Duffieux, Institut FEMTO-ST, UMR 6174 CNRS Université de Franche-Comté, F-25030 Besançon cedex, France.
authors.forename: John M
authors.initials: JM
authors.lastname: Dudley
authors.affiliation: Centre de Physique Théorique, CNRS, Ecole Polytechnique, F-91128 Palaiseau, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Couairon
authors.affiliation: Département d'Optique P. M. Duffieux, Institut FEMTO-ST, UMR 6174 CNRS Université de Franche-Comté, F-25030 Besançon cedex, France.
authors.forename: Francois
authors.initials: F
authors.lastname: Courvoisier