Full-field imaging-based instantaneous hyperspectral absolute refractive index measurement

Area of Science:

• Optical Physics
• Spectroscopy
• Materials Science

Background:

• Traditional multispectral refractometers measure refractive index (RI) serially at discrete wavelengths.
• Existing methods can be time-consuming and may not capture the full spectral behavior of samples.

Purpose of the Study:

• To demonstrate a white light, full-field imaging refractometer for instantaneous multispectral RI measurement.
• To enable comprehensive analysis of clear liquid-gel samples across the visible spectrum.

Main Methods:

• Development of a broad optical bandwidth refractometer utilizing white light full-field imaging.
• Implementation of a system for instantaneous acquisition of spectral RI data.
• Detailed system design, calibration, and validation using a known sample.

Main Results:

• Achieved hyperspectral measurement of RI in the range of 1.30-1.70 from 400-700 nm.
• Reported a maximum error of 0.0036 units (0.24%) at 414 nm for a sample with RI=1.50.
• Demonstrated instantaneous, full-spectrum RI measurement capability.

Conclusions:

• The developed white light refractometer provides rapid and accurate multispectral RI measurements.
• This technology offers a significant advancement over serial measurement techniques.
• The system is suitable for characterizing the optical properties of various liquid-gel materials.