A rigorous theoretical analysis of the diffraction of light on a sub-wavelength metallic slit is presented. Solution of the 2D Sommerfeld integral shows that the so-called quasi-cylindrical wave is a convolution of a first order cylindrical harmonic with the transit surface Plasmon polariton, a 1D spatial distribution along the metallic interface extending outside the slit. The quasi-cylindrical wave is not a surface wave but is a scattered field propagating along the interface but also in the entire space of the media adjacent to the slit. We demonstrate that this field can be enhanced by the surface Plasmon resonance, when the dielectric function of the metal tends to the negative of the permittivity of the medium above the slit.

Date Published: 26 November 2012
PDF: 6 pages
Proc. SPIE 8556, Holography, Diffractive Optics, and Applications V, 85560F (26 November 2012); doi: 10.1117/12.2001668

Published in SPIE Proceedings Vol. 8556:
Holography, Diffractive Optics, and Applications V
Yunlong Sheng; Chongxiu Yu; Linsen Chen, Editor(s)