Mass Diffusivity Measurements Using Interferometry

We know that the diffusion is defined as the movement of molecules under a potential gradient. It is characterized by the diffusion coefficient. Diffusion coefficient determination can be done via various techniques, but in this paper, we have had a broad look at interferometry based optical methods for diffusion coefficient determination. The basis for these techniques is the formation of fringes due to the change in optical path length of light as it passes through a concentration distribution. Diffusion determination techniques like phase- shifting interferometry, common path shearing interferometry, holographic interferometry, electronic speckle pattern interferometry, multiple-beam interferometry and Michaelson interferometry were discussed in the paper. Various aspects of the techniques for determination of diffusivity using interferometry based optical techniques were looked at.