Realizing multi-function absorptions through arbitrary octagonal meta-atoms.

Area of Science:

• Electromagnetic Metamaterials
• Nanophotonics
• Applied Physics

Background:

• Metasurface absorbers (MA) traditionally rely on regular structures, limiting their functional diversity.
• Achieving tunable and multifunctional absorption properties in metasurfaces remains a significant challenge.

Purpose of the Study:

• To design and demonstrate an irregular metasurface absorber (MA) with enhanced and tunable absorption functionalities.
• To develop a computational framework for predicting geometric parameters and inverse design of MAs based on target absorption spectra.

Main Methods:

• Proposed an irregular metasurface absorber (MA) utilizing octagonal meta-atoms with multiple geometric degrees of freedom.
• Employed a deep neural network integrated with the particle swarm optimization algorithm for spectral prediction and inverse design.

Main Results:

• The irregular MA structure demonstrated versatile functionalities: perfect absorption, multi-peak absorption, and absorption with a filtering window.
• Achieved a low mean-square error of 0.0008 for spectrum prediction and 0.0031 for inverse design, validating the computational approach.

Conclusions:

• The proposed irregular MA design offers a pathway to multifunctional electromagnetic structures.
• This approach holds significant potential for advanced applications in tunable metasurfaces and metamaterials.