Wavelength-dependent refractive index measurement of transparent materials via image analysis

A non-destructive image-analysis method for measuring the refractive index and dispersion of transparent materials without surface polishing or complex preparation is introduced. The technique uses a sugar solution of known refractive index as a reference medium. It determines the sample's refractive index by analyzing the disappearance of boundary contrast in charge coupled device camera-captured images. Dispersion is obtained by employing multiple bandpass filters to record measurements at different wavelengths. The method achieves precision in the order of 10-2 and is demonstrated as a proof of concept for evaluating the refractive index of unpolished, irregular, or inhomogeneous materials. It is ideal for the rapid evaluation of fragile, irregular, and complex materials such as glass and crystal optical materials.