High-Efficiency Visible Transmitting Polarizations Devices Based on the GaN Metasurface

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Metasurfaces offer precise control over light's amplitude, phase, and polarization.
• Existing metasurfaces often have limitations in simultaneously modulating orthogonal polarizations, especially in the visible range.

Purpose of the Study:

• To develop a high-efficiency metasurface for simultaneous modulation of orthogonal linear polarizations in the visible light spectrum.
• To utilize gallium nitride (GaN) as a novel dielectric material for advanced optical device design.

Main Methods:

• Designing GaN nanobricks with tailored geometric sizes to control transmitted phase modulation.
• Simulating and fabricating metasurfaces capable of achieving a 2π phase shift for orthogonal polarizations.
• Demonstrating device functionalities including beam splitting, focusing, and multi-polarization metalenses.

Main Results:

• Achieved nearly full 2π phase modulation for both orthogonal linear polarizations with high transmission (>90%).
• Successfully designed and realized visible beam splitters and focusing lenses at 530 nm.
• Demonstrated a 3D metalens capable of simultaneously focusing X, Y, 45°, and 135° linear polarizations.

Conclusions:

• Gallium nitride (GaN) metasurfaces are effective for high-efficiency, simultaneous modulation of orthogonal polarizations in the visible range.
• The proposed method enables the creation of multifunctional optical devices by extending modulation dimensions.
• This work paves the way for advanced polarization-based optical measurements and devices.