18 May 2011 Bi-metal coated aperture SNOM probes
Author Affiliations +
Abstract
Aperture probes of scanning near-field optical microscopes (SNOM) offer resolution which is limited by a sum of the aperture diameter at the tip of a tapered waveguide probe and twice the skin depth in metal used for coating. An increase of resolution requires a decrease of the aperture diameter. However, due to low energy throughput of such probes aperture diameters usually are larger than 50 nm. A groove structure at fiber core-metal coating interface for photon-to-plasmon conversion enhances the energy throughput 5-fold for Al coated probes and 30-fold for Au coated probes due to lower losses in the metal. However, gold coated probes have lower resolution, first due to light coupling from the core to plasmons at the outside of the metal coating, and second due to the skin depth being larger than for Al. Here we report on the impact of a metal bilayer of constant thickness for coating aperture SNOM probes. The purpose of the bilayer of two metals of which the outer one is aluminum and the inner is a noble metal is to assure low losses, hence larger transmission. Using body-of-revolution finite-difference time-domain simulations we analyze properties of probes without corrugations to measure the impact of using a metal bilayer and choose an optimum bi-metal configuration. Additionally we investigate how this type of metalization works in the case of grooved probes.
© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Tomasz J. Antosiewicz, Tomasz J. Antosiewicz, Piotr Wróbel, Piotr Wróbel, Tomasz Szoplik, Tomasz Szoplik, } "Bi-metal coated aperture SNOM probes", Proc. SPIE 8070, Metamaterials VI, 80700Z (18 May 2011); doi: 10.1117/12.886834; https://doi.org/10.1117/12.886834
PROCEEDINGS
9 PAGES


SHARE
RELATED CONTENT

Bandgaps of photonic crystal composed of metallic cylinders
Proceedings of SPIE (October 05 2006)
Performance of SNOM probes with one groove at core ...
Proceedings of SPIE (December 14 2010)
Dielectric-metal-dielectric nanotip for SNOM
Proceedings of SPIE (May 12 2009)
High resolution SNOM probes
Proceedings of SPIE (November 19 2008)

Back to Top