ABSTRACT
Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Water-
loo, Ontario, Canada
Nirmalya Ghosh
Department of Physical Sciences, Indian Institute of Science Education and Research (IISER),
Kolkata, Mohanpur, West Bengal, India
Alex Vitkin
Division of Biophysics and Bioimaging, Ontario Cancer Institute; Department of Medical Bio-
physics and Radiation Oncology, University of Toronto, 610 University Avenue, Toronto, Ontario
M5G 2M9, Canada
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
2.2 Fundamentals of Polarization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
2.3 Experimental Polarimetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
2.4 Forward Modeling of Polarization Transfer in Complex Random Media . . . . . . . . . . . . . . . . . . . 85
2.5 Interpretation and Decomposition of Mueller Matrices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
2.6 Biomedical Applications of Polarimetric Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
2.7 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Studies of polarization properties of scattered light from turbid materials such as biological tis-
sues have received considerable recent attention, because of the potential of polarimetric approaches
for tissue imaging, characterization, and diagnosis. Polarization can be used as an effective tool to
discriminate against multiply scattered light (acting as a gating / contrast mechanism) and thus may
facilitate enhancement of contrast and resolution in tissue imaging. Moreover, the intrinsic tissue
polarimetry characteristics contain a wealth of morphological and functional information, which
can be exploited for quantitative tissue characterization and assessment. However, in a complex
randommedium like tissue, numerous complexities due to multiple scattering and spatially inhomo-
geneous birefringence, as well as simultaneous occurrences of several polarization events, present
formidable challenges for biomedical tissue polarimetry. In this chapter, we discuss advances in
polarized light methodologies to overcome some of these challenges, and present illustrative exam-
ples of biomedical applications. Specifically, we review the basic polarimetry formalisms, outline
the specific issues in tissue polarimetry, discuss the Stokes and Mueller experimental systems, and
describe forward modeling of polarized light propagation in tissue. We then focus on inverse anal-
ysis for polarimetric results quantification and applications to quantitative tissue assessment. The
other classes of polarization applications in biomedicine, that of tissue imaging and polarization mi-
Biophotonics:
croscopy, are also mentioned in passing, with sufficient references to corresponding recent reviews
of these topics.
