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Proceedings Paper

Focusing of radially polarized light with corrugated silver nanolayer
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Paper Abstract

In this paper we present technical details of a metal nanolens in the form of a free standing silver film with no hole on the optical axis and double-sided concentric corrugations. In a numerical experiment we analyze the nanolens performance, that is transmission and focusing of radially polarized beams of different full widths at half maximum and wavelengths from the visible range. Corrugations of the front surface couple incident light to surface plasmons and those on the back surface allow efficient reradiation. The silver lens of thickness 100 nm has five concentric corrugations of periodicity 500 nm with groove depth and width equal 40 nm and 100 nm, respectively. Focusing properties of such a structure are analyzed and optimized for wavelengths in the range from 400 to 600 nm. At intensity transmission of 10-25% of incident light achievable focal spot areas reach down to 0.15λ2. For different illumination parameters the nanolens has focal lengths from 1 to 2 wavelengths. Without contribution of evanescent waves it focuses a far-field source into a farfield spot. The nanolens acts like a refractive optical system of high numerical aperture close to unity. Nanolenses of this kind can be used as light couplers in nanooptics.

Paper Details

Date Published: 12 May 2009
PDF: 9 pages
Proc. SPIE 7353, Metamaterials IV, 73530X (12 May 2009); doi: 10.1117/12.821371
Show Author Affiliations
Piotr Wrobel, Univ. of Warsaw (Poland)
Jacek Pniewski, Univ. of Warsaw (Poland)
Tomasz J. Antosiewicz, Univ. of Warsaw (Poland)
Tomasz Szoplik, Univ. of Warsaw (Poland)

Published in SPIE Proceedings Vol. 7353:
Metamaterials IV
Vladimir Kuzmiak; Peter Markos; Tomasz Szoplik, Editor(s)

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