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Probing highly confined optical fields in the focal region of a high NA parabolic mirror with subwavelength spatial resolution
Author(s) -
Debus C.,
Lieb M. A.,
Drechsler A.,
Meixner A. J.
Publication year - 2003
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1046/j.1365-2818.2003.01091.x
Subject(s) - optics , polarization (electrochemistry) , physics , numerical aperture , raster scan , cardinal point , electric field , transverse plane , parabolic reflector , focal length , image resolution , wavelength , chemistry , structural engineering , quantum mechanics , lens (geology) , engineering
Summary Parabolic mirrors with a high numerical aperture can be conveniently used to produce highly confined optical fields in the focal region. Furthermore, these fields can have interesting polarization behaviour due to the high numerical aperture. In particular, if the mirror is illuminated with a size matched radially polarized or azimuthally polarized doughnut mode, the electric field has in the focal region almost exclusively a longitudinal or a transverse polarization component. Such field distributions are interesting for applications in confocal or near‐field optical microscopy. Here we present experimental results where we have probed some of these field distributions by raster scanning a fine gold tip in nanometer steps through the focal region and detecting the scattered light intensity. The measured intensity patterns are compared with corresponding vector‐field calculations.