All silicon MIR super absorber using fractal metasurfaces

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Perfect absorbers are crucial for applications like photodetectors and solar energy conversion.
• Mid-infrared (MIR) wavelengths offer significant advantages for various technological applications.
• Traditional metallic absorbers face limitations in certain energy harvesting scenarios.

Purpose of the Study:

• To propose and simulate a novel fractal mid-infrared (MIR) broadband absorber.
• To investigate the absorption enhancement capabilities of the proposed structure.
• To explore the use of doped silicon (D-Si) as a plasmonic material in the MIR region.

Main Methods:

• A Metal-Dielectric-Metal (MDM) structure was designed based on the Sierpinski carpet fractal.
• Doped silicon (D-Si) and silicon carbide (SiC) were used as the material layers.
• The 3D finite element method (FEM) was employed for numerical simulations using COMSOL Multiphysics.

Main Results:

• The fractal absorber demonstrated high absorption enhancement across the MIR spectrum (3-9 µm).
• Doped silicon showed superior performance over traditional metals for MIR plasmonic applications.
• The D-Si/SiC/D-Si structure achieved broadband absorption characteristics.

Conclusions:

• The proposed fractal absorber design offers significant potential for MIR applications.
• Doped silicon is a promising material for efficient energy harvesting and plasmonic devices in the mid-infrared.
• The study highlights the advantages of semiconductor materials for plasmonic devices, including CMOS compatibility and simpler fabrication.