title: Generation of a hollow dark spherical spot by 4pi focusing of a radially polarized Laguerre-Gaussian beam.
abstract: The properties of the focal spot for 4pi focusing with radially polarized first-order Laguerre-Gaussian beams are calculated. It is shown that a focal spot that has an extremely sharp dark region at the center and an almost-perfect spherical symmetry can be achieved. When such a hollow dark spherical spot is used in 4pi fluorescence depletion microscopy, an axial FWHM spot size of approximately 39 nm and a transverse FWHM spot size of approximately 64 nm can be achieved simultaneously in a practical system.
authors.affiliation: Department of Physics, Budapest University of Technology and Economics, Hungary. nandor.bokor@weizmann.ac.il
authors.forename: Nándor
authors.initials: N
authors.lastname: Bokor
authors.forename: Nir
authors.initials: N
authors.lastname: Davidson