Simultaneous Multi-frequency Topological Edge Modes between One-dimensional Photonic Crystals

TL;DR

This paper theoretically demonstrates that one-dimensional binary centrosymmetric photonic crystals can support topological edge modes across all photonic band gaps, enabling multi-frequency robust photonic applications.

Contribution

It introduces a novel theoretical framework showing multi-frequency topological edge modes in 1D photonic crystals under weak dispersion conditions.

Findings

Topological edge modes exist at all band gaps in 1D photonic crystals.

Edge modes can be engineered at center or zone boundary gaps.

Potential for robust multi-frequency photonic devices.

Abstract

We show theoretically that, in the limit of weak dispersion, one-dimensional (1D) binary centrosymmetric photonic crystals can support topological edge modes in all photonic band gaps. By analyzing their bulk band topology, these "harmonic" topological edge modes can be designed in a way that they exist at all photonic band gaps opened at the center of the Brillouin Zone, or at all gaps opened at the zone boundaries, or both. The results may suggest a new approach to achieve robust multi-frequency coupled modes for applications in nonlinear photonics, such as frequency up-conversion.