The Theory of SNOM: A Novel Approach

TL;DR

This paper applies electromagnetic theory and transfer matrix methods to analyze and improve the transmission efficiency of SNOM tips, including innovative tip modifications like coaxial cables, without compromising resolution.

Contribution

It introduces a transfer matrix based calculation for SNOM analysis and explores coaxial tip design to enhance light transmission.

Findings

Transfer matrix method effectively models SNOM tip behavior.

Introducing a coaxial wire can significantly increase transmission.

Enhanced transmission does not reduce resolution.

Abstract

In this paper we consider the application of electromagnetic theory to the analysis of the Scanning Near-field Optical Microscope (SNOM) in order to predict experimentally observable quantities such as the transmission or reflection coefficients for a particular tip-surface configuration. In particular we present the first application of a transfer matrix based calculation to this challenging problem by using an adaptive co-ordinate transformation to accurately model the shape of the SNOM tip. We also investigate the possibility of increasing the transmitted light through the SNOM tip by introducing a metal wire into the centre of the tip. This converts the tip into a co-axial cable. We show that, in principle, this can dramatically improve the transmission characteristics without having a detrimental effect on the resolution.