Steven L. Jacques, Ph.D., Department of Electrical and Computer Engineering Oregon Graduate Institute, Portland, Oregon, USA. email: jacquess@ohsu.edu, https://omlc.org

Basic science studies .

The orientation of linearly polarized light becomes randomized as it passes through scattering media such as tissues. This process can be characterized by an angular diffusivity, X [rad²/mean free path or mfp]. We measured the value of X for polystyrene microsphere solutions and for tissue samples of chicken muscle and liver. Information on X will allow modeling of the depth of polarization images.

The incident parallel light is denoted as a vertical arrow. Both scattering and randomly oriented birefringence cause the orientation of polarization to migrate both clockwise and counterclockwise, denoted by angle theta. The progressive loss in orientation is modeled as a diffusion in theta space.

For organized tissues which present an oriented birefringence, linearly polarized light will rotate in one preferential theta direction. This preliminary work does not consider such organization, although our current work is now considering oriented birefringent tissues.