Ultra-broadband, wide angle absorber utilizing metal insulator multilayers stack with a multi-thickness metal surface...

Area of Science:

• Photonics and optical metamaterials.
• Nanotechnology and thin-film devices.

Background:

• Broadband light absorbers are crucial for applications like solar energy harvesting and optical sensing.
• Existing designs often struggle to achieve wide absorption bandwidths and wide-angle performance simultaneously.

Purpose of the Study:

• To propose and demonstrate a facile fabrication route for a metal-insulator-metal-insulator (MIMI) multilayer stack.
• To achieve ultra-broadband and wide-angle light absorption by engineering the thickness of the middle metal layer.

Main Methods:

• Numerical simulations were performed to investigate the effect of varying metal layer thickness on light absorption.
• Fabrication of the proposed MIMI multilayer structures.
• Experimental characterization of the fabricated devices to verify numerical predictions.

Main Results:

• A non-uniform metal layer thickness significantly broadens the absorption bandwidth compared to a planar design.
• The proposed multi-thickness design achieved an absorption bandwidth of 1060 nm (350 nm–1410 nm).
• Numerical findings were experimentally verified, showing good agreement.

Conclusions:

• The variant metal thickness approach is effective for creating ultra-broadband absorbers.
• This MIMI multilayer design offers a promising solution for applications requiring efficient light absorption over a wide spectral range and angle.