title: Direct generation of Bessel beams.
abstract: Two implementations are identified to create a Bessel beam directly, i.e. without the spatial filtering of an initially Gaussian beam. The first implementation is based on a resonator configuration whose lowest-loss transverse mode is a Bessel beam. Numerical simulation to corroborate the geometrical optical arguments is presented. The second implementation is based on the theorem that the angular-plane wave spectrum of a Bessel beam is composed of a cone of wave vectors. This cone is also generated through a phase-matching condition in a four-wave mixing process. This leads to the conclusion that anti-Stokes radiation generated in a nonlinear material will leave the substrate under the form of a Bessel beam.
authors.affiliation: VDM Laser Optics, Eke-Nazareth, Belgium. vdm@vdm-lo.be
authors.forename: Peter
authors.initials: P
authors.lastname: Muys
authors.forename: Eefje
authors.initials: E
authors.lastname: Vandamme