Biomedical Applications of Polarimetry

Non- or minimally-invasive data collection is highly desirable for gathering the broad base of information that facilitates moving technology to the point of care. Polarimetry has been making this transition for years. Early forms of polarization-sensitive optics involved custom multiplexing a series of images to generate a single image, but today’s snapshot polarimeters are readily commercially available. The research presented in this dissertation advances three areas of polarimetric imaging: First, this research develops a reflectance-based measurement for tracking changes in the alignment of dynamically loaded soft tissue, specifically tendon. This work highlights a range of mounting angles across which signal strength is agnostic to sensor location. Second, it compares a high dynamic range division-of-focal-plane (DoFP) polarimeter with a standard DoFP polarimeter, highlighting both the current limitations of polarimetry and future areas for sensor improvement. The incorporation of a DoFP polarization filter with a high dynamic range sensor represents an important advance in DoFP polarimetry, in that the high-dynamic range pixels can compensate for the reduced photon flux at the photosensor caused by the nano-wire filters. Finally, this research identifies a polarization-based neural signal, with major implications for non-invasively tracking neural activity, including the first tandem recording of optical and electrical activity from a single region. In conclusion, this work makes important advances across a range of polarimetric applications