The asymmetric lossy near-perfect lens

TL;DR

This paper proposes an asymmetric near-perfect lens using a negative refractive index slab bounded by media of different positive indices, demonstrating improved robustness against absorption and subwavelength imaging capabilities.

Contribution

It extends the perfect lens concept to asymmetric structures, analyzing surface states and absorption effects, especially with silver slabs, for enhanced near-field imaging.

Findings

Asymmetric lens amplifies evanescent waves effectively.

Robustness against absorption improves image resolution.

Subwavelength imaging achievable despite retardation effects.

Abstract

We extend the ideas of the recently proposed perfect lens [J.B. Pendry, Phys. Rev. Lett. {\bf 85}, 3966 (2000)] to an alternative structure. We show that a slab of a medium with negative refractive index bounded by media of different positive refractive index also amplifies evanescent waves and can act as a near-perfect lens. We examine the role of the surface states in the amplification of the evanescent waves. The image resolution obtained by this asymmetric lens is more robust against the effects of absorption in the lens. In particular, we study the case of a slab of silver, which has negative dielectric constant, with air on one side and other media such as glass or GaAs on the other side as an `asymmetric' lossy near-perfect lens for P-polarized waves. It is found that retardation has an adverse effect on the imaging due to the positive magnetic permeability of silver, but we conclude that subwavelength image resolution is possible inspite of it.