Surface plasmon resonance prism coupler for enhanced circular dichroism sensing

Area of Science:

• Optics and Photonics
• Biophysical Chemistry

Background:

• Circular dichroism (CD) spectroscopy is crucial for analyzing chiral molecules.
• Existing CD detection methods face limitations in sensitivity and handling scattering effects.

Purpose of the Study:

• To develop a novel, highly sensitive method for enhanced CD detection.
• To accurately measure CD and degree of polarization (DOP) in samples, including those with scattering.
• To validate the method's performance through simulations and experiments.

Main Methods:

• Integration of a surface plasmon resonance (SPR) prism coupler with polarization scanning ellipsometry.
• Derivation of an analytical model for extracting CD and DOP properties.
• Numerical simulations to confirm model validity and assess sensitivity.
• Experimental validation using chlorophyllin samples with and without scattering.

Main Results:

• The analytical model accurately extracts CD and DOP, accounting for scattering.
• Simulations demonstrate high sensitivity (10^-5~10^-6 RIU) for refractive index detection.
• Experimental results confirm linear correlation between CD response and chlorophyll concentration.
• High sensitivity of CD measurements to polarization scanning angle was observed.

Conclusions:

• The proposed SPR and polarization scanning ellipsometry method offers enhanced CD detection capabilities.
• The technique is effective for analyzing samples with and without scattering effects.
• Polarization scanning ellipsometry holds significant potential for high-resolution CD detection applications.