High-efficiency and ultra-broadband asymmetric transmission metasurface based on topologically coding optimization...

Area of Science:

• Metamaterials and Nanophotonics
• Electromagnetics and Optics
• Communication Systems Engineering

Background:

• Asymmetric transmission is crucial for communication systems, but current metasurfaces suffer from narrow bandwidth and low efficiency due to dispersion.
• Existing ultra-broadband metasurfaces face challenges with transmission fluctuations and limited performance.
• Developing efficient and wideband asymmetric transmission devices remains a significant challenge in applied physics and engineering.

Purpose of the Study:

• To propose and demonstrate a novel strategy for achieving high-efficiency, ultra-broadband asymmetric transmission using an ultra-thin metasurface.
• To overcome the inherent limitations of narrow bandwidth and low efficiency in existing asymmetric transmission metasurfaces.
• To provide a pathway for developing advanced polarization transformers and polarization-controlled devices.

Main Methods:

• Utilizing a topologically coding optimization method to design an ultra-thin metasurface.
• Employing a genetic algorithm to optimize a meta-atom composed of orthogonal gratings and a central lattice particle.
• Tuning the coupling among metallic layers within the meta-atom to suppress transmission fluctuations.

Main Results:

• The developed metasurface demonstrates high efficiency and ultra-broadband asymmetric transmission.
• Experimental results show over 95% perfect reflection for y-polarized incidence and over 80% cross-polarization transmission for x-polarized incidence.
• The device operates effectively across a wide frequency range from 5.3 GHz to 16.7 GHz.

Conclusions:

• The proposed metasurface design successfully achieves high-efficiency and ultra-broadband asymmetric transmission.
• The optimized central lattice effectively suppresses transmission fluctuations, leading to broad bandwidth and high transmission.
• This research offers a promising approach for high-performance, broadband polarization transformers and polarization-controlled devices across various frequency domains.