Broadening Bandwidths of Few-Layer Absorbers by Superimposing Two High-Loss Resonators

Area of Science:

• Materials Science
• Optics
• Renewable Energy

Background:

• Efficient absorption of solar radiation is crucial for applications like seawater desalination and icephobicity.
• Existing metal-insulator-metal (MIM) planar absorbers have limitations in bandwidth and angular performance.

Purpose of the Study:

• To develop a broadband solar absorber with enhanced absorption efficiency and angular stability.
• To investigate a flexible, low-cost metasurface absorber for practical solar heat utilization.

Main Methods:

• Proposed a few-layer absorber structure by superimposing two high-loss resonances.
• Fabricated a flexible 1D non-noble metasurface absorber using a single evaporation step.
• Conducted simulations and experiments to evaluate absorption efficiency, bandwidth, and angular performance.

Main Results:

• Achieved an average absorption efficiency over 97% from 350 to 1200 nm.
• Obtained a bandwidth of 1000 nm (410-1410 nm) for absorption greater than 90%.
• Demonstrated high absorption (>90% at 65°, >80% at 75°) with excellent angular insensitivity.
• Showcased rapid ice-melting capability with lower illumination intensity compared to previous studies.

Conclusions:

• The developed metasurface absorber offers superior broadband absorption and angular stability.
• The flexible, low-cost, and large-area fabrication potential makes it advantageous for practical solar heat utilization.
• This work presents an effective pathway for designing advanced metasurface absorbers for renewable energy applications.