Plasmonic hybridization generation in self-aligned disk/hole nanocavities for multi-resonance sensing

Area of Science:

• Plasmonics
• Nanophotonics
• Biosensing

Background:

• Plasmonic nanostructures offer potential for ultra-sensitive, label-free biomolecule detection.
• Near-field enhancement and nanoscale localization are key features of plasmonic sensors.

Purpose of the Study:

• To demonstrate photonic plasmonic hybridization in a self-aligned disk/hole nanocavity array.
• To investigate the sensing performance of hybridized modes in nanogap and nanooverlap configurations.

Main Methods:

• Fabrication of disk/hole nanocavity arrays with adjustable pillar height to create nanogap and nanooverlap.
• Analysis of hybridized modes, focusing on in-phase (bonding) and out-of-phase (antibonding) coupling.
• Systematic investigation of bulk refractive index sensitivity and surface sensitivity for sensing applications.

Main Results:

• Disk/hole arrays exhibit three hybridized modes with high absorption due to dipolar mode coupling.
• Nanooverlap configuration shows a significant resonant frequency shift in the bonding mode and enhanced near-field localization (decay length down to 3.8 nm).
• Both nanogap and nanooverlap structures demonstrate high sensitivity, with the nanooverlap offering tunable surface sensitivity for different biomolecule sizes.

Conclusions:

• The proposed disk/hole array mechanism enables photonic plasmonic hybridization with tunable sensing properties.
• The nanooverlap configuration provides superior near-field localization and potential for selective detection of biomolecules.
• This platform is highly valuable for developing advanced, high-sensitivity biosensing technologies.