A new UV imaging polarimeter design was demonstrated by Optical Coating Solutions, Inc. (OCS) as a proof-of-concept breadboard in a 2016 Phase I effort (NASA Contract NNX16CA44P). A version of that generic design is proposed for atmospheric studies in a follow-on effort. The new polarimeter design can operate to wavelengths as short as 260nm and does not employ electronic or mechanical modulation to measure polarization properties. The advantages overcome the limitations present in current polarimeter designs. Polarimetry of atmospheres to wavelengths shorter than 400 nm will assist in the determination of the distribution vs. altitude of aerosols, size, shape, and absorption properties of the scattering particles, and is useful for separating multiply- and singly-scattering components. Compact in volume, the Passive UV Imaging Polarimeter can be deployed as multiple units aimed to different view angles for simultaneous wide- angle coverage. The unique compact architecture is well suited for extended space missions because it satisfies low power and weight budget requirements, has inherently high radiation-tolerant components. In addition, it incorporates a built-in stability monitor with two polarization-references that promotes high polarimetric accuracy. Modifications resulting in prototype model will advance the TRL to 5 or 6. Potential NASA Applications (Limit 1500 characters, approximately 150 words) Extending space missions to UV wavelengths for PACE earth climate and resource monitoring compliments the studies of aerosols, dust and smoke, water and ice clouds, greenhouse gases, vegetation and ground surfaces, hydrosols, and oceanic biogeochemistry. UV polarimetry extends remote studies of atmospheres and surfaces of terrestrial, planetary, moons of outer planets, asteroid, and cometary bodies. Potential Non-NASA Applications (Limit 1500 characters, approximately 150 words) UV polarimetry in aviation, automotive, and marine environments helps to distinguish ice-coated surfaces from liquid water coatings on wings, and can distinguish between natural vs man-made surfaces. Identification is improved in battlefield and marine environments. In medical and clinical applications, can detect abnormal scatter patterns in melanoma and deeper tissues and in burns and wounds.
