Multi-octave metasurface-based refractory superabsorber enhanced by a tapered unit-cell structure

Area of Science:

• Metamaterials and Nanophotonics
• Optical Engineering
• Materials Science

Background:

• Metasurfaces offer unique electromagnetic properties.
• Developing efficient broadband absorbers is crucial for energy applications.
• High-temperature stability is essential for practical absorber deployment.

Purpose of the Study:

• To propose and analyze an ultra-broadband metasurface-based perfect absorber.
• To investigate the absorption characteristics and tunability of the proposed structure.
• To evaluate its suitability for thermal energy harvesting and solar absorption.

Main Methods:

• Design of a metasurface comprising truncated cone-shaped structures surrounded by TiN/SiN conical rings.
• Utilizing refractory materials for high-temperature structural stability.
• Numerical simulations to analyze absorption spectra, angular dependence, and parameter optimization.

Main Results:

• Achieved ultra-broadband absorption from 0.2-4.5 µm with >90% absorption.
• Demonstrated super absorption (>97.40%) from 0.2-3.25 µm with average absorption >99%.
• Showcased near-insensitivity to incident angles for TE polarization and weak dependence for TM polarization.

Conclusions:

• The proposed metasurface perfect absorber exhibits excellent broadband absorption and high efficiency.
• Its structural stability at high temperatures and angular tolerance make it promising for solar energy harvesting.
• The tunable absorption through cone angle offers design flexibility for specific applications.