Interlayer coupled dual-layer metagratings for broadband and high-efficiency anomalous reflection

Area of Science:

• Electromagnetics
• Metamaterials
• Optics

Background:

• Metagratings offer high-performance wavefront engineering but suffer from narrow operating bandwidth.
• Conventional metagratings struggle to maintain efficiency over a wide range of frequencies.

Purpose of the Study:

• To design and demonstrate a dual-layer metagrating with enhanced interlayer couplings.
• To achieve high-efficiency and broadband anomalous reflection in the microwave spectrum.

Main Methods:

• Utilized a combination of the eigenmode expansion (EME) algorithm and particle swarm optimization (PSO) for design.
• Incorporated enhanced intralayer and interlayer couplings within the dual-layer metagrating structure.
• Experimentally validated the performance of the proposed metagrating.

Main Results:

• The dual-layer metagrating achieved high-efficiency anomalous reflection across a broad spectrum.
• An average efficiency of approximately 90% was recorded within the 14.7 to 18 GHz frequency range.
• Demonstrated the ability to reroute a normally incident wave to the +1 order diffraction direction.

Conclusions:

• The proposed dual-layer metagrating overcomes the bandwidth limitations of conventional devices.
• This technology enables sophisticated beam manipulation and has potential applications in spatial dispersive devices.
• The study highlights the potential of multi-layer metagratings with complex coupling dynamics for advanced optical applications.