title: Self and forced periodic arrangement of multiple filaments in glass.
abstract: The formation of permanent periodic structural changes in fused silica induced by the multifilamentation process was investigated. A cylindrical lens was used to focus 800 nm 50 fs pulses with 0.5 - 3 mJ energy down to a line, resulting in a quasi-periodic linear self-arrangement of multiple filaments (MF). The quasi-period of multiple filaments is shown to be uniquely defined by the critical power of the material and the peak intensity on the sample entrance surface. A novel technique to control this spatial self-arrangement of MF is demonstrated based on the use of a binary phase mask. This technique allowed us to decrease the relative variation of spacing between the adjacent tracks of refractive index modifications by a factor of 4 as compared with the case without the phase mask. 3D + time numerical simulations qualitatively reproduce the main features of multiple filament formation obtained in the experiment.
authors.affiliation: Centre d'Optique, Photonique et Laser et Département de Physique, de Génie Physique et d'Optique, Université Laval, 2375 rue de la Terrasse, bureau 2104,Québec, Qc G1V 0A6, Canada. jean-philippe.berube.2@ulaval.ca
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Bérubé
authors.forename: Réal
authors.initials: R
authors.lastname: Vallée
authors.forename: Martin
authors.initials: M
authors.lastname: Bernier
authors.forename: Olga
authors.initials: O
authors.lastname: Kosareva
authors.forename: Nikolay
authors.initials: N
authors.lastname: Panov
authors.forename: Valery
authors.initials: V
authors.lastname: Kandidov
authors.forename: See Leang
authors.initials: SL
authors.lastname: Chin