3D conical helix metamaterial-based isotropic broadband perfect light absorber

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Metamaterials offer unique light manipulation properties.
• Broadband and isotropic perfect light absorbers are crucial for various optical applications.
• Existing designs often face limitations in bandwidth, angular dependence, or polarization sensitivity.

Purpose of the Study:

• To design and fabricate an isotropic broadband perfect light absorber in the near-infrared (NIR) spectrum.
• To utilize a single resonator unit cell in a 3D metamaterial structure.
• To achieve high average absorbance with wide operational bandwidth and angular/polarization independence.

Main Methods:

• Design of a 3D metamaterial unit cell comprising a gold conical helix on a silicon pillar with a silicon substrate back reflector.
• Electromagnetic simulations to predict absorption characteristics.
• Experimental fabrication and optical characterization of the proposed metamaterial absorber.

Main Results:

• Demonstrated a broadband absorption band exceeding 3 µm in the 1.5-4.5 µm wavelength range.
• Achieved an average absorbance greater than 90% across the operational bandwidth.
• Verified incident angle and polarization independent absorption through numerical and experimental analyses.

Conclusions:

• The developed 3D metamaterial absorber is an efficient solution for broadband light absorption in the NIR range.
• The design's isotropic and polarization-independent operation enhances its applicability in diverse optical systems.
• This work paves the way for advanced applications in sensing, thermal imaging, and energy harvesting.