Computational investigation of nanohole array based SPR sensing using phase shift.

Area of Science:

• Nanophotonics and Plasmonics
• Biosensing Technologies
• Surface Science

Background:

• Monitoring refractive index changes is crucial for detecting molecular interactions.
• Traditional Surface Plasmon Resonance (SPR) sensors often require complex optical setups.
• Developing high-resolution, easily implementable sensors is an ongoing challenge in molecular detection.

Purpose of the Study:

• To introduce a novel high spatial resolution sensor for detecting refractive index variations.
• To leverage extraordinary optical transmission (EOT) via SPR for signal transduction.
• To assess the sensor's performance, including sensitivity, dynamic range, and linearity.

Main Methods:

• Fabrication of metallic surfaces with 2D nanoholes.
• Utilizing Surface Plasmon Resonance (SPR) to induce Extraordinary Optical Transmission (EOT).
• Simulating various device design parameters to optimize performance.
• Detecting optical phase changes for signal transduction.

Main Results:

• Achieved a shot-noise limited sensitivity threshold of 4.37 x 10⁻⁹ refractive index units (RIU).
• Demonstrated a wide dynamic range of 0.17 RIU.
• Observed a linear phase change across the entire refractive index detection range.

Conclusions:

• The nanoholes-based SPR sensor offers high spatial resolution and dense integration capabilities.
• The sensor design simplifies practical implementation compared to traditional Kretschmann SPR setups.
• The sensor exhibits favorable high-resolution and wide dynamic range attributes, comparable or superior to existing SPR sensors.