Prevalence of Two-Dimensional Photonic Topology.

Area of Science:

• Condensed matter physics
• Photonics
• Materials science

Background:

• Topological photonics investigates exotic phenomena in photonic crystals.
• The prevalence of topological phases in photonics remains an open question.

Purpose of the Study:

• To determine the abundance of stable, fragile, and higher-order topological phases in synthetic 2D photonic crystals.
• To analyze the influence of symmetry, dielectric contrast, polarization, and time-reversal symmetry breaking on topological phase prevalence.

Main Methods:

• Symmetry analysis of 550,000 synthetic 2D photonic crystals.
• Systematic investigation across 11 plane groups.

Main Results:

• A general abundance of nontrivial band topology was found.
• Stable topology is prevalent in transverse electric polarization under time-reversal symmetry.
• Fragile topology is nearly absent, and Chern insulating phases are abundant in time-reversal broken settings.

Conclusions:

• Symmetry, polarization, and time-reversal breaking significantly influence topological phase occurrence.
• The findings suggest broad opportunities for designing novel topological photonic devices.