Holographic measurement of diffusion coefficients

A holographic interferometer specially designed for measuring diffusion coefficients in transparent mixtures is described. The diffusion coefficient is simply and directly measured from the interferograms using a finite fringe system intentionally introduced into the interferometer. Preliminary results concerning the KCl-water diffusion system are in reasonable agreement with other methods. The results obtained for diffusion of diphenyl ether in hexadecane are also presented.