Enhanced Surface Plasmon Resonance Sensing via Kramers-Kronig Phase Extraction

Area of Science:

• Optics and Photonics
• Analytical Chemistry
• Materials Science

Background:

• Surface Plasmon Resonance (SPR) is a label-free optical technique widely used for detecting molecular interactions.
• Conventional SPR sensing relies on measuring changes in the resonance angle or wavelength.
• Limitations exist in sensitivity and detection limits for certain applications.

Purpose of the Study:

• To introduce a novel method for enhancing SPR sensing performance.
• To leverage Kramers-Kronig (K-K) relations for improved phase extraction from SPR reflection spectra.
• To achieve lower detection limits for refractive index variations in aqueous solutions.

Main Methods:

• Utilized Kramers-Kronig (K-K) relations to extract phase information from SPR reflection spectra.
• Applied the K-K relations to analyze phase shifts in response to changes in refractive index.
• Compared the sensitivity and detection limits with conventional SPR peak shift methods.

Main Results:

• Achieved a phase shift sensitivity of 3400°/RIU.
• Improved SPR detection limits to 9 × 10^-6 RIU.
• Demonstrated a four-fold increase in sensitivity compared to conventional SPR peak shift detection.

Conclusions:

• The K-K relations offer a powerful approach to enhance SPR phase extraction and sensing capabilities.
• This method provides significantly improved sensitivity and lower detection limits for refractive index measurements.
• The advancement holds promise for more precise biosensing and environmental monitoring using spectrometers.