Amorphous Photonic Lattices: Band Gaps, Effective Mass and Suppressed Transport

TL;DR

This paper explores amorphous photonic lattices that exhibit band gaps without Bragg diffraction, demonstrating unique localization properties and extending the concept of effective mass to disordered systems.

Contribution

It provides both theoretical and experimental evidence of band gaps in amorphous photonic lattices lacking Bragg diffraction, and introduces the effective mass concept in such disordered structures.

Findings

Amorphous lattices exhibit band gaps without Bragg peaks.

Defect states in the gap are more localized than Anderson localization.

Effective mass concept applies to amorphous photonic systems.

Abstract

We present, theoretically and experimentally, amorphous photonic lattices exhibiting a band-gap yet completely lacking Bragg diffraction: 2D waveguides distributed randomly according to a liquid-like model responsible for the absence of Bragg peaks as opposed to ordered lattices containing disorder, which always exhibit Bragg peaks. In amorphous lattices the bands are comprised of localized states, but we find that defect states residing in the gap are more localized than the Anderson localization length. Finally, we show how the concept of effective mass carries over to amorphous lattices.