Robust method to determine the resolution of a superlens by analyzing the near-field image of a two-slit object

TL;DR

This paper introduces a quantitative analytical method to determine the resolution of superlenses by fitting near-field images of a two-slit object, enabling rapid assessment of superresolution lens performance.

Contribution

The paper presents a novel analytical approach for accurately estimating superlens resolution from near-field imaging data, improving upon traditional rough estimates.

Findings

Method effectively fits experimental data to theoretical profiles

Applied to three literature cases demonstrating versatility

Enables quick and precise resolution assessment

Abstract

In the last decade, metamaterials-based superlenses, with a resolution below Abbe's diffraction limit, have emerged. To obtain a rough estimate of the resolution of such superlenses, imaging of two subwavelength slits, separated by a subwavelength gap \textit{d} is typically performed. The resolution $\Delta$ of the lens corresponds to the minimum possible gap $d_{min}$ for which a distinct image of the two slits can be resolved ($\Delta \sim d_{min}$). In this letter, we present a more quantitative estimate of the resolution of manufactured lenses by fitting analytical near-field image profiles, obtained from imaging a two-slit object with a theoretical negative-index lens of known resolution, to experimental data. We conclude the discussion by applying our analytical method to 3 case examples of superlensing from the literature. As shown, this method is particularly attractive for rapidly assessing the performance of fabricated superresolution lenses.