Reconfigurable Light Imaging in Photonic Higher-Order Topological Insulators

Area of Science:

• Photonics
• Condensed Matter Physics
• Materials Science

Background:

• Topological phases of matter offer robust wave control via edge states.
• Higher-order topological insulators (HOTIs) provide lower-dimensional topological states for wave manipulation.
• Conventional HOTIs often lack tunability due to symmetry protection, limiting applications.

Purpose of the Study:

• To realize reconfigurable light imaging using topological states in a 2D photonic HOTI.
• To explore the interplay of corner states and anti-chiral edge states for versatile wave control.
• To demonstrate the potential of tunable photonic devices for advanced applications.

Main Methods:

• Fabrication of a 2D photonic HOTI using a honeycomb lattice of yttrium iron garnet (YIG) rods.
• Application of opposite magnetic fields to sublattices to realize a modified Haldane model with anti-chiral edge modes.
• Breaking inversion symmetry by adjusting rod radii to introduce valley-dependent topological edge states and corner states.

Main Results:

• Observation of anti-chiral edge states and valley-dependent topological edge states.
• Emergence of topological corner states within the valley edge gap.
• Demonstration of reconfigurable light imaging, including a multiplexing device, switchable imaging, and selective object imaging.

Conclusions:

• The proposed photonic HOTI enables versatile and reconfigurable light imaging by combining corner and anti-chiral edge states.
• This work highlights the potential for tunable and reconfigurable functions in intelligent photonic devices.
• The findings may inspire advancements in topological switching, image processing, and nonreciprocal integrated photonics.