title: Tighter focusing with a parabolic mirror.
abstract: We demonstrate experimentally and theoretically that a parabolic mirror (PM) with a high numerical aperture (NA) of 1 focuses a radially polarized laser mode to the smallest diffraction-limited spot at a fixed NA and wavelength, having an area of 0.134 lambda(2). The measurements were performed with a confocal microscope, using the PM as a focusing and collecting element. The results stand in accordance with the theoretical calculations presented by Davidson and Bokor [Opt. Lett. 29, 1318 (2004)], who predicted a reduction in the total focal spot size of 43% as compared with an aplanatic lens.
authors.affiliation: Institute of Physical Theoretical Chemistry, University of Tuebingen, Auf der Morgenstelle, Tuebingen, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Stadler
authors.forename: C
authors.initials: C
authors.lastname: Stanciu
authors.forename: C
authors.initials: C
authors.lastname: Stupperich
authors.forename: A J
authors.initials: AJ
authors.lastname: Meixner