Multifunctional Hyperbolic Nanogroove Metasurface for Submolecular Detection

Area of Science:

• Plasmonics and Nanophotonics
• Biosensing Technologies
• Metamaterials Engineering

Background:

• Metasurfaces enable enhanced light-matter interactions for sensing applications.
• Plasmonic sensing platforms are crucial for detecting minute changes in refractive index.
• Existing metamaterials have limitations in sensitivity and detection resolution.

Purpose of the Study:

• To design and investigate a hyperbolic metasurface with nanogroove structures for enhanced plasmonic sensing.
• To explore the modification of surface plasmon wave properties by nanogroove geometry.
• To achieve ultrahigh sensitivity and submolecular detection limits for biomolecules.

Main Methods:

• Design of a subwavelength-scale hyperbolic metasurface with tunable nanogroove width and periodicity.
• Exploitation of the epsilon-near-zero (ENZ) effect for tightly confined, diffraction-free surface plasmon polaritons.
• Phase and Goos-Hänchen shift measurements for refractive index sensing.

Main Results:

• Achieved ultrahigh phase sensitivity of 30,373 deg RIU⁻¹ and Goos-Hänchen shift sensitivity of 10.134 mm RIU⁻¹.
• Demonstrated a refractive index resolution of 10⁻⁸ RIU for glycerol solution.
• Attained detection limits of 0.1 × 10⁻¹⁸ m for Bovine Serum Albumin (BSA) and below 1 × 10⁻¹⁵ m for biotin.
• Observed a two-orders-of-magnitude improvement in sensing performance compared to state-of-the-art plasmonic metamaterials.

Conclusions:

• The designed groove hyperbolic metasurface significantly enhances plasmonic sensing capabilities.
• This platform enables submolecular-level detection of biomolecules with unprecedented resolution.
• The findings pave the way for next-generation ultrasensitive biosensors.