title: Detecting axial heterogeneity of birefringence in layered turbid media using polarized light imaging.
abstract: The structural anisotropy of biological tissues can be quantified using polarized light imaging in terms of birefringence; however, birefringence varies axially in anisotropic layered tissues. This may present ambiguity in result interpretation for techniques whose birefringence results are averaged over the sampling volume. To explore this issue, we extended the polarization sensitive Monte Carlo code to model bi-layered turbid media with varying uniaxial birefringence in the two layers. Our findings demonstrate that the asymmetry degree (ASD) between the off-diagonal Mueller matrix elements of heterogeneously birefringent samples is higher than the homogenously birefringent (uniaxial) samples with the same effective retardance (magnitude and orientation). We experimentally verified the validity of ASD as a birefringence heterogeneity measure by performing polarized light measurements of bi-layered elastic and scattering polyacrylamide phantoms.
authors.affiliation: Division of Biophysics and Bioimaging, Ontario Cancer Institute/University Health Network and Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, Ontario M5G 2M9,  Canada.
authors.forename: Sanaz
authors.initials: S
authors.lastname: Alali
authors.forename: Yuting
authors.initials: Y
authors.lastname: Wang
authors.forename: I Alex
authors.initials: IA
authors.lastname: Vitkin