Measurement and monitoring of diffusion process is important in many areas of physical, chemical and biological sciences. Usually interferometric methods are used for this. Even though very accurate, they require controlled environments (especially to be isolated from external noise) and should adhere to stringent optical considerations. Single beam optical techniques are more suitable in noisy environments. Since a diffusing medium has a non-uniform refractive index distribution, a ray passing through such a medium will deflect towards regions of higher refractive index. If this deflection can be measured somehow, it can be used for finding the refractive index gradient and hence the refractive index distribution inside the medium. Here a method is proposed to measure these deflections and hence the diffusion coefficient using active optical elements, by converting the incident light into a spatially varying polarization pattern.

Date Published: 18 June 2007
PDF: 6 pages
Proc. SPIE 6616, Optical Measurement Systems for Industrial Inspection V, 661643 (18 June 2007); doi: 10.1117/12.726006

Published in SPIE Proceedings Vol. 6616:
Optical Measurement Systems for Industrial Inspection V
Wolfgang Osten; Christophe Gorecki; Erik L. Novak, Editor(s)