Abstract
We investigate both experimentally and theoretically the far-field diffraction patterns of single circular apertures as a function of their diameters and at a given illumination wavelength . We observe the transition between the well-known pseudoscalar regime of large holes () and the less-known vectorial regime of subwavelength ones (). Four different diffraction regimes are identified for different regions, each one with its polarization dependence. A thorough comparison with a theoretical model, which takes into account both finite hole size and the dielectric properties of the metal, allows us to explain and understand the physical processes leading to this behavior. Our results reveal the subtle interplay between two competing factors, one related to polarization symmetries associated with surface-plasmon excitations and the other originating in the coupling of the field to the waveguide mode of the aperture.
- Received 2 February 2012
DOI:https://doi.org/10.1103/PhysRevLett.109.023901
© 2012 American Physical Society
Synopsis
A New Window on Nanometer Apertures
Published 12 July 2012
Experiment and theory combine to give a more complete picture of a fundamental problem in diffraction optics.
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