Revisiting the Perfect Lens with Loss

TL;DR

This paper demonstrates that due to dispersion and loss in negative index media, evanescent waves cannot be refocused, making sub-diffraction imaging impossible, challenging the ideal of a perfect lens.

Contribution

It revisits the perfect lens concept by incorporating realistic dispersive and lossy properties, showing evanescent waves cannot be refocused in practice.

Findings

Evanescent waves are refracted into decaying propagating waves.

Different spatial frequencies are separated in space and time.

Sub-diffraction imaging is fundamentally unachievable with lossy negative index media.

Abstract

We reconsider the refraction of evanescent waves at an interface between air and negative index medium under the assumption that negative index medium is necessarily dispersive and lossy. We show that all evanescent waves in air will be refracted into decaying propagating waves inside a negative index medium, with different spatial frequency components having different propagation directions which are separated both in time and space; hence no refocus of these evanescent waves is possible. Accordingly, all information encoded by evanescent waves will be lost in the image making sub-diffraction-limited imaging impossible.