Gauge-Tunable Uniform Delocalization of Higher-Order Topological Photonic Modes

Area of Science:

• Topological photonics
• Condensed matter physics
• Materials science

Background:

• Higher-order topological photonic systems usually exhibit localized corner states.
• Existing systems lack scalability and tunability for practical applications.

Purpose of the Study:

• To uncover a distinct regime of uniformly delocalized higher-order topological modes.
• To enable tunable reconfiguration of topological modes without sacrificing protection.
• To bridge the gap between scalable optical mode area and robust topological protection.

Main Methods:

• Investigating higher-order topological photonic systems with multiple spatially varying Dirac mass terms.
• Utilizing chiral symmetry to engineer mode properties.
• Theoretical modeling and experimental validation in photonic crystals.

Main Results:

• Discovered uniformly delocalized higher-order topological modes with large-area, sublattice-locked profiles.
• Demonstrated that these modes remain pinned at zero energy, independent of system size.
• Showcased a tunable gauge degree of freedom for controlled reconfiguration without loss of topological protection.
• Achieved excellent agreement between theoretical predictions and experimental results in photonic crystals.

Conclusions:

• The findings introduce a novel regime of topological photonics with uniformly delocalized modes.
• The demonstrated tunability and robustness are crucial for scalable topological optical devices.
• This work provides a direct pathway for designing robust, large-area topological optical devices.