Mesoscopic self-collimation and slow light in all-positive index layered photonic crystals

TL;DR

This paper demonstrates a novel mesoscopic self-collimation effect in all-positive index layered photonic crystals, enabling diffraction-free and slow light propagation with low air filling ratios.

Contribution

It introduces an electromagnetic theory for self-collimation in layered photonic crystals and combines slow light with self-collimation in low-filling-ratio structures.

Findings

Observation of diffraction-free beams in layered photonic crystals.

Theoretical framework for self-collimation with dispersion relation curvature compensation.

Achieved slow light regime with low air filling ratio.

Abstract

We demonstrate a mesoscopic self-collimation effect in photonic crystal superlattices consisting of a periodic set of all-positive index 2D photonic crystal and homogeneous layers. We develop an electromagnetic theory showing that diffraction-free beams are observed when the curvature of the optical dispersion relation is properly compensated for. This approach allows to combine slow light regime together with self-collimation in photonic crystal superlattices presenting an extremely low filling ratio in air.