Refractive index measurement using single fiber reflectance spectroscopy.

Area of Science:

• Optics
• Spectroscopy
• Biomedical Engineering

Background:

• Accurate measurement of refractive indices is crucial for understanding light-matter interactions in diverse materials.
• Existing methods for refractive index determination can be limited in scope or applicability to different sample types.

Purpose of the Study:

• To present and validate a novel method using single fiber reflectance spectroscopy (SFRS) for measuring refractive indices.
• To assess the accuracy and wavelength dependence of SFRS across transparent and turbid media.
• To explore the potential of SFRS for in vivo measurements of biological tissues.

Main Methods:

• Utilized single fiber reflectance spectroscopy to probe optical properties.
• Tested the method on transparent liquid samples, liquid turbid media, and solid turbid samples (human skin).
• Analyzed the influence of wavelength and sample properties on measurement accuracy.

Main Results:

• Achieved high accuracy for transparent liquids (within 0.2%) with accuracy increasing at longer wavelengths.
• Demonstrated good accuracy for liquid turbid media (within 0.3%) with accuracy increasing at shorter wavelengths.
• Identified critical dependence on optical contact for solid turbid samples like human skin.

Conclusions:

• Single fiber reflectance spectroscopy is a versatile and accurate technique for determining refractive indices.
• The method shows promise for non-invasive, in vivo refractive index measurements of biological tissues.
• Optimization of fiber-sample contact is essential for accurate measurements of solid, turbid biological samples.