Creating topological exceptional point by on-chip all-dielectric metasurface

Area of Science:

• Photonics and Metasurfaces
• Topological Physics
• Nanophotonics

Background:

• Topological metasurfaces, non-Hermitian systems, offer unique properties like exceptional points (EPs).
• Existing metasurfaces often use plasmonic materials, causing ohmic losses and limiting integration.
• Free-space configurations hinder compact, multi-device integration.

Purpose of the Study:

• To experimentally demonstrate an on-chip topological metasurface in an all-dielectric architecture.
• To engineer the topological phase encircling an EP.
• To enable practical augmented reality (AR) functionalities through holographic visualization.

Main Methods:

• Utilized silicon (Si) meta-atoms on a silicon nitride (Si3N4) waveguide.
• Massively screened meta-atom geometry to achieve a 2π-topological phase shift by encircling an EP.
• Integrated Pancharatnam-Berry (PB) phase for decoupling polarization channels.

Main Results:

• Achieved a 2π-topological phase shift by encircling an EP in an all-dielectric metasurface.
• Demonstrated independent encoding for holographic generations by decoupling circular polarization channels.
• Enabled floating holographic visualizations for AR applications.

Conclusions:

• The all-dielectric on-chip metasurface eliminates ohmic losses, enhancing device compatibility.
• This platform facilitates integration with other on-chip meta-devices.
• Presents promising applications for next-generation AR, data storage, and optical displays.