Optical spin-symmetry breaking for high-efficiency directional helicity-multiplexed metaholograms

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Symmetric spin-orbit interactions (SOIs) limit metasurface applications, particularly in holographic imaging.
• Asymmetric SOIs offer solutions for applications like asymmetric data inscription and dual-side displays.
• Low-loss dielectric materials are crucial for efficient realization of exotic optical phenomena.

Purpose of the Study:

• To demonstrate an asymmetric SOI-dependent transmission-type metasurface in the visible domain.
• To overcome the limitations of symmetric SOIs in helicity-multiplexed metasurfaces.
• To enable bi-directional asymmetric wavefront generation with high efficiency.

Main Methods:

• Fabrication of a transmission-type metasurface using hydrogenated amorphous silicon (a-Si:H) nanoresonators.
• Utilizing asymmetric spin-orbit interactions for wavefront control.
• Characterization of the metasurface's performance in the visible spectrum.

Main Results:

• Achieved high transmission efficiencies for two distinct, on-axis wavefronts generated in antiparallel directions.
• Demonstrated asymmetric wavefront generation capabilities.
• Showcased the potential for bi-directional helicity-multiplexed metasurfaces.

Conclusions:

• The proposed a-Si:H metasurface effectively utilizes asymmetric SOIs for advanced holographic applications.
• Hydrogenated amorphous silicon offers a cost-effective, CMOS-compatible alternative for visible light metasurfaces.
• The design is suitable for high-efficiency, multifunctional, and chip-integrated optical devices.