title: Axial emission and spectral broadening in self-focusing of femtosecond Bessel beams.
abstract: We report on the experimental observations of on-axis spectral broadening arising from self-focusing of the axicon-generated femtosecond Bessel beam in water. The observed spectral broadening is interpreted by a nonlinearly phase-matched four-wave mixing process involving the intense conical pump, the axial signal and a conical idler wave.
authors.forename: A
authors.initials: A
authors.lastname: Dubietis
authors.forename: P
authors.initials: P
authors.lastname: Polesana
authors.forename: G
authors.initials: G
authors.lastname: Valiulis
authors.forename: A
authors.initials: A
authors.lastname: Stabinis
authors.forename: P
authors.initials: P
authors.lastname: Di Trapani
authors.forename: A
authors.initials: A
authors.lastname: Piskarskas