Plasmonic Metasurface for Spatially Resolved Optical Sensing in Three Dimensions

Area of Science:

• Nanotechnology and Materials Science
• Plasmonics and Nanophotonics
• Chemical and Physical Sensing

Background:

• Localized surface plasmon resonance (LSPR) in metallic nanoparticles offers high sensitivity for detecting surface events.
• Existing nanoplasmonic sensors are typically 2D, limiting sensing capabilities to a single plane.
• There is a need for 3D sensing strategies to probe processes in multiple dimensions.

Purpose of the Study:

• To develop a 3D nanoplasmonic sensor capable of probing spatially distinct locations simultaneously.
• To demonstrate real-time, multi-location sensing using a rationally designed plasmonic metasurface.
• To investigate layer-specific properties of materials using 3D sensing.

Main Methods:

• Fabrication of a plasmonic metasurface with stacked silver nanodisks separated by a SiO2 dielectric layer.
• Design of the metasurface to exhibit two spectrally separated LSPR peaks corresponding to distinct sensing locations.
• Utilizing the sensor to measure layer-specific glass transition temperatures of a polymer bilayer in a single experiment.

Main Results:

• The designed metasurface successfully generated two distinct and spectrally addressable LSPR sensing peaks.
• Spatially separated sensing locations in the axial direction were achieved, enabling 3D sensing.
• Layer-specific glass transition temperatures of PMMA and P(MMA-MAA) bilayer films were accurately determined in real-time.

Conclusions:

• A novel 3D nanoplasmonic sensor strategy enabling simultaneous probing of spatially distinct locations has been demonstrated.
• This approach allows for real-time, layer-specific analysis of material properties.
• The work stimulates the development of advanced sensors with multiple, individually addressable detection elements for complex analyses.