Tunable index metamaterials made by bottom-up approaches

Area of Science:

• Materials Science
• Nanotechnology
• Optics

Background:

• Metamaterials offer unique optical properties but face challenges due to metal losses and costly fabrication.
• Existing metamaterial fabrication methods are often expensive and have low throughput, limiting technological applications.

Purpose of the Study:

• To present a new, easily realizable double fishnet metamaterial design.
• To overcome the limitations of conventional metamaterials by employing cost-effective and scalable fabrication techniques.

Main Methods:

• Utilized nanosphere lithography to create a polystyrene sphere monolayer template.
• Employed metallic electrodeposition for infiltrating two symmetric gold layers with a controlled air gap.
• Varied sphere diameter and gap width to tune the metamaterial's effective refractive index.

Main Results:

• Successfully fabricated double fishnet metamaterials with tunable refractive indices ranging from 1.5 to -1.0 in the near-infrared spectrum.
• Demonstrated good agreement between experimental optical measurements and finite-difference time-domain (FDTD) simulations.
• Identified key design parameters influencing the metamaterial's optical response.

Conclusions:

• The proposed fabrication method combining nanosphere lithography and metallic electrodeposition is effective for producing high-performance metamaterials.
• The double fishnet metamaterial design allows for precise tuning of the refractive index, offering a promising alternative for optical applications.
• This work provides a pathway for the cost-effective and scalable implementation of metamaterials in advanced technologies.