Dual-spectrum transparent random encoding metasurface for scattering reduction and electromagnetic shielding

Area of Science:

• Metamaterials and Nanophotonics
• Electromagnetic Compatibility
• Optical Engineering

Background:

• Advanced optical windows require simultaneous high transmittance and electromagnetic (EM) protection.
• Existing solutions often compromise performance in one or more spectral ranges or EM shielding effectiveness.
• Metasurfaces offer tunable electromagnetic properties for novel device functionalities.

Purpose of the Study:

• To propose and demonstrate a dual-spectrum transparent random encoding metasurface (DTREM).
• To achieve excellent radar cross-section (RCS) reduction and enhanced EM protection for optical windows.
• To ensure high EM shielding and transmittance in visible and infrared spectra.

Main Methods:

• Fabrication of a DTREM using an easy-to-implement metal mesh technology.
• Theoretical analysis of physical parameter constraints for the metal mesh.
• Optimization of the coding array using a simulated annealing algorithm.
• Experimental validation of transmittance, RCS reduction, and EM shielding effectiveness.

Main Results:

• Achieved dual-spectrum transmittance of 89.5% at 550 nm and 90.8% in the 3.0-5.0 μm range.
• Demonstrated RCS reduction exceeding 10 dB across 13.6-17.2 GHz.
• Obtained a shielding effectiveness of 23.8 dB over the X-Ku band.

Conclusions:

• The developed DTREM effectively integrates high optical transmittance with robust EM protection and stealth capabilities.
• The simulated annealing algorithm significantly improved RCS reduction performance.
• The proposed metasurface is a promising solution for integrated optoelectronic detection platforms.