Refractive index determination of buffer solutions from visible to near-infrared spectral range for multispectral quantitative phase imaging using a calibrated Abbe refractometer

Information about the refractive index difference between a biological material and its surrounding medium is of key importance in various research fields in biophotonics. However, the optical properties of many physiological buffer solutions are not well characterized over a broad spectral range. In this study, we measure the refractive index of mainly transparent liquids commonly used for live cell imaging and tissue embedding in the wavelength range from 500 nm to 1100 nm utilizing a modified and calibrated Abbe refractometer. The presented approach for obtaining multi-spectral refractive index data builds the basis to retrieve the dispersion coefficients of various physiological buffer solutions.