Evanescent waves in photonic crystals and image of Veselago lens

TL;DR

This paper investigates evanescent waves in photonic crystals near the Gamma-point, clarifying their decay behavior, and discusses implications for Veselago lens imaging and superlensing limitations.

Contribution

It demonstrates that evanescent modes in photonic crystals decay in the bulk and clarifies the conditions under which surface waves can enhance imaging.

Findings

Evanescent modes decay in the bulk of photonic crystals.

Surface waves can amplify evanescent waves, potentially improving Veselago lens imaging.

A contradiction between perfect lens theory and wave optics is identified.

Abstract

It is shown that negative electric permittivity and magnetic permeability recently discovered in a photonic crystal in the vicinity of the Gamma-point are properties of propagating modes only. The evanescent modes rather decay than increase in the bulk of the crystal though they may be amplified by surface waves. If surface support such waves, the evanescent waves may improve the image of a thin Veselago lens. It is shown that a ``perfect lens'' contradicts to the wave optics and a criterion of ``superlensing'' is formulated.