LAUSR

We describe a new measurement technique to determine the refractive index (RI) of solid particles by monitoring the simultaneous scattering of light from suspension with a camera and the value of the RI with a refractometer. Our immersion solid matching method is based on the solidification process of the liquid continuously changing the RI as a function of time. The principle of the determination is based on finding the RI matching point of the particle and the liquid during the solidification. The traditional liquid immersion method is based on a set of immersion liquids with different refractive indices, while the proposed method requires only a small amount of a single immersion liquid. The method was tested using calcium fluoride (CaF2) particles with a varnish immersion liquid. The RI value of CaF2 was obtained to be consistent with the literature values, thus indicating the proper functioning of the proposed procedure.