Beam propagation in finite size photonic crystals and metamaterials

TL;DR

This paper analyzes how beams propagate inside finite photonic crystals and metamaterials, revealing that the beam shift isn't always aligned with the normal to the dispersion curve, due to evanescent waves.

Contribution

It provides a detailed analysis of beam propagation in finite photonic structures and introduces a renormalized diagram to accurately predict beam emergence directions.

Findings

Beam shift can deviate from the normal to the dispersion curve.

Evanescent waves significantly influence beam propagation.

A renormalized diagram accurately predicts beam emergence direction.

Abstract

The recent interest in the imaging possibilities of photonic crystals (superlensing, superprism, optical mirages etc...) call for a detailed analysis of beam propagation inside a finite periodic structure. In this paper, an answer to the question "where does the beam emerge?" is given. Contrarily to common knowledge, it is not always true that the shift of a beam is given by the normal to the dispersion curve. This phenomenon is explained in terms of evanescent waves and a renormalized diagram that gives the correct direction is given.