Giant Extra-Ordinary Near Infrared Transmission from Seemingly Opaque Plasmonic Metasurface: Sensing Applications.

Area of Science:

• Plasmonics
• Metasurfaces
• Nanophotonics

Background:

• Conventional metasurfaces often exhibit limited light transmission.
• Controlling electromagnetic field coupling is crucial for enhancing light transmission through nanostructures.

Purpose of the Study:

• To demonstrate giant, wavelength-selective near-infrared light transmission (>90%) through a novel plasmonic metasurface.
• To investigate the role of electromagnetic field coupling and structural parameters in achieving enhanced transmission.
• To explore the application of this metasurface in high-sensitivity refractive index sensing.

Main Methods:

• Fabrication of a plasmonic metasurface composed of two alternating metal nano-slits arrays (MNSAs).
• Optimization of interlayer spacing, lateral overlap, fill factors, and plasmonic metals for maximum light transmission.
• Utilizing coupled plasmonic modes and extended surface plasmons (ESPs) for light manipulation.

Main Results:

• Achieved >90% near-infrared light transmission through the opaque metasurface.
• Demonstrated wavelength-selective transmission due to perfect coupling of plasmonic modes.
• Optimized metasurface achieved a maximum sensitivity of 1435.71 nm/RIU and a figure of merit (FOM) of 80 RIU⁻¹ for refractive index sensing.

Conclusions:

• The study confirms the concept of light funneling through subwavelength structures via plasmons.
• The developed metasurface is suitable for highly sensitive, flexible, and cost-effective extraordinary optical transmission (EOT)-based sensors.
• This work opens avenues for advanced photonic devices and sensing technologies.