Two-Dimensional Topology Optimized Nonlocal Metasurfaces for Augmented Reality

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Metasurfaces are explored for augmented reality (AR) to replace bulky optics.
• Current metasurface combiners lack spectral multifunctionality, limiting light separation.
• Existing nonlocal metasurfaces often have reduced efficiency due to design constraints.

Purpose of the Study:

• To develop a compact, multifunctional free-space combiner for AR using a nonlocal metasurface.
• To achieve high spectral selectivity and efficiency for separating ambient and display light.
• To enable advanced optical displays with improved color purity and reduced power consumption.

Main Methods:

• Topology optimization of a nonlocal metasurface.
• Utilizing first-order reflective diffraction for high-Q resonances at RGB wavelengths.
• Introducing 2D design freedom into resonant waveguide gratings for freeform structures.

Main Results:

• Demonstrated high diffraction efficiencies and narrow spectral bandwidths.
• Achieved precise wavelength selectivity with vivid color reproduction.
• Validated experimental results showing strong suppression of spectral leakage.
• Integrated metasurface into a free-space AR platform with high color purity and reduced display power.

Conclusions:

• The topology-optimized nonlocal metasurface enables compact, multifunctional free-space combiners for AR.
• This approach offers a promising path toward advanced optical displays and spectrally selective photonic systems.
• The design overcomes limitations of existing metasurface combiners, enhancing AR performance.