title: Fourier-optical selection of higher order transverse modes in broad area lasers.
abstract: A partially and a highly antire ection coated broad area laser are operated in an external cavity Fourier-optical 4f set-up to experimentally investigate transverse mode selection. The external cavity consists of a lens and a spatial frequency filter. Running freely the lasers show non-stationary filamentation. Placing the spatial filter unit directly onto the optical axis gives cw fundamental mode operation and a transverse shift of the spatial filter in the plane of the active region allows for selective excitation of higher order modes.
authors.forename: S
authors.initials: S
authors.lastname: Wolff
authors.forename: D
authors.initials: D
authors.lastname: Messerschmidt
authors.forename: H
authors.initials: H
authors.lastname: Fouckhardt