Limitations on Sub-Diffraction Imaging with a Negative Refractive Index Slab

TL;DR

This paper examines the limitations of sub-diffraction imaging using a negative index slab, highlighting sensitivity to parameters and the necessity of precise design for achieving super-resolution.

Contribution

It analyzes the sensitivity of subwavelength focusing to slab parameters and clarifies conditions needed for practical super-resolution imaging.

Findings

Subwavelength resolution depends critically on slab parameters.

Connection between slab plasmon modes and imaging performance.

Achieving super-resolution requires precise design parameters.

Abstract

Recently it has been proposed that a planar slab of material, for which both the permittivity and permeability have the values of -1, could bring not only the propagating fields associated with a source to a focus, but could also refocus the nonpropagating near-fields, thereby achieving a subdiffraction image. In this work we discuss the sensitivity of the subwavelength focus to various slab parameters, pointing out the connection to slab plasmon modes. We also note and resolve a paradox associated with the perfect imaging of a point source. We conclude that subwavelength resolution is achievable with available technology, but only by implementation of a critical set of design parameters.