Temperature-Dependent Refractive Index Determination from Critical Angle Measurements:  Implications for Quantitative...

Area of Science:

• Optoelectronics
• Materials Science
• Analytical Chemistry

Background:

• Surface plasmon resonance spectroscopy (SPR) is sensitive to bulk solution optical properties.
• Accurate bulk solution refractive index data is vital for quantitative thin-film sensing.
• Temperature, concentration, and wavelength significantly influence bulk solution refractive index.

Purpose of the Study:

• To demonstrate critical angle measurements for accurate, independent determination of bulk solution refractive index.
• To investigate the impact of bulk solution variations on two-color SPR sensing.
• To highlight the importance of accounting for bulk refractive index in SPR applications.

Main Methods:

• Utilized critical angle measurements for refractive index determination.
• Performed measurements under varying solution temperatures, concentrations, and excitation wavelengths.
• Analyzed the implications of bulk solution variations in two-color SPR sensing of ultrathin organic films.

Main Results:

• Successfully demonstrated accurate, independent determination of bulk solution refractive index.
• Showcased the influence of temperature, concentration, and wavelength on refractive index.
• Quantified the significant impact of uncorrected bulk solution effects on SPR sensing sensitivity.

Conclusions:

• Critical angle measurements are essential for precise SPR thin-film sensing.
• Accurate bulk refractive index data improves the sensitivity and reliability of SPR.
• This method is invaluable for temperature-dependent SPR and unknown solution index scenarios.