Paper
29 April 2010 Optimisation of a plasmonic nanolens: increase of transmission and focal length
Author Affiliations +
Abstract
In a numerical experiment, we optimise performance of plasmonic lenses with different structures of single metal nanolayers. The nanolenses, either with double sided grooved or with slits act like classical, high-numerical aperture, refractive objectives. Their focal regions are well defined and different from those of diffractive optical elements. The narrowest rotationally symmetric foci are achieved for a Laguerre-Gauss intensity profile with radial polarization. The highest transmission reaching 80% is achieved for high slit width-to-lattice constant ratios when light is waveguided in annular slits. In grooved and continuous metal lenses transmission reaches 30% due to resonant tunnelling of plasmons. Location of slit/groove edges, which act as sources of spherical waves, and light intensity at them decides on interference of radial and longitudinal electric field components in focal region. Proper choice of lattice constants and surface structure allows for focal length several times larger than the free space light wavelength. All simulations are made using body-of-revolution finite difference time domain method and Drude model parameters of silver. In simulations we accept parameters of the nanolenses which are possible to fabricate with technical equipment available to us.
© (2010) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Piotr Wróbel, Tomasz J. Antosiewicz, and Tomasz Szoplik "Optimisation of a plasmonic nanolens: increase of transmission and focal length", Proc. SPIE 7711, Metamaterials V, 77110I (29 April 2010); https://doi.org/10.1117/12.855511
Advertisement
Advertisement
RIGHTS & PERMISSIONS
Get copyright permission  Get copyright permission on Copyright Marketplace
KEYWORDS
Lenses

Metals

Plasmonics

Silver

Finite-difference time-domain method

Dielectrics

Plasmons

Back to Top