Portable device based on beam deflection for refractive index mapping and diffusion coefficient measurement

Nonuniform refractive index distributions in transparent mediums are of interest as it gives rise to a modification of the probe light beam passing through such mediums. Various properties of the probe beam can be used to quantify the modification happening to the probe beam. One of these properties is the deflection of the beam. This could be used to map and quantify the spatiotemporal evolution of refractive index distribution in such mediums. The deflections could be measured by imaging the deflection of structured line pattern projected through such a system. We describe the development of a compact, portable device for mapping of refractive index distributions as well measurement of the diffusion coefficient of liquid solutions. The method and device are demonstrated by the real-time display of the refractive changes as well as measurement of diffusion coefficients in diffusing binary liquid solutions.