Theory and experiments of disorder-induced resonance shifts and mode edge broadening in deliberately disordered photonic crystal waveguides

TL;DR

This study combines theoretical modeling and experimental validation to investigate how deliberate disorder affects the photon density of states and mode broadening in photonic crystal waveguides, revealing disorder-induced shifts and broadening effects.

Contribution

It introduces a comprehensive theoretical model that accounts for both deliberate and intrinsic disorder, validated by experimental data, advancing understanding of disorder effects in photonic crystals.

Findings

Disorder causes a mean blueshift in the density of states.

Disorder leads to broadening of the photonic density of states.

Good qualitative agreement between theory and experiment was achieved.

Abstract

We study both theoretically and experimentally the effects of introducing deliberate disorder in a slow-light photonic crystal waveguide on the photon density of states. We first introduce a theoretical model that includes both deliberate disorder through statistically moving the hole centres in the photonic crystal lattice and intrinsic disorder caused by manufacturing imperfections. We demonstrate a disorder-induced mean blueshift and an overall broadening of the photonic density of states for various amounts of deliberate disorder. By comparing with measurements from a GaAs photonic crystal waveguide, we find good qualitative agreement between theory and experiment which highlights the importance of carefully including local field effects for modelling high-index contrast perturbations. Our work also demonstrates the importance of using asymmetric dielectric polarizabilities for modelling positive and negative dielectric perturbations when modelling a perturbed dielectric interface in photonic crystal platforms.