Multifold Enhancement of Chiroptical Sensing with Plasmonic Diffraction Gratings

Area of Science:

• Plasmonics
• Chiroptical Sensing
• Nanophotonics

Background:

• Chiral substance differentiation is vital in pharmacology, medicine, and biochemistry.
• Enantiomer-specific activity necessitates precise detection methods.
• Current chiroptical sensing methods require improvement for sensitivity and real-time analysis.

Purpose of the Study:

• To analyze the enhancement of chiroptical sensitivity in a plasmonic platform.
• To investigate the use of a structured plasmonic film (diffraction grating) for improved chiral detection.
• To quantify the sensitivity improvement based on differential reflection and chirality.

Main Methods:

• Theoretical and numerical analysis of a plasmonic diffraction grating.
• Investigation of angle-resolved surface plasmon resonance.
• Quantification of differential-reflection observables dependence on the chirality parameter.

Main Results:

• The plasmonic grating platform demonstrated a significant enhancement in chiral sensitivity.
• Sensitivity increased by approximately 2 orders of magnitude compared to unstructured films.
• Rayleigh's anomaly effect was identified as the cause for the enhanced sensitivity.

Conclusions:

• A novel plasmonic grating platform offers superior chiroptical sensing capabilities.
• The concept of using resonant and diffractive gratings can boost chiral sensitivity.
• This platform shows promise for detecting extremely low concentrations of chiral substances in real-time.