Persistent Link:
http://hdl.handle.net/10150/193923
Title:
MULTIANGLE SPECTROPOLARIMETRIC IMAGER (MSPI)
Author:
Mahler, Anna-Britt
Issue Date:
2010
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Substantial impacts of aerosols on climate and public health underscore the need for accurate characterization of atmospheric aerosol distributions and microphysical properties. The Multiangle SpectroPolarimetric Imager (MSPI) combines accurate multispectral, multiangle, and polarimetric technologies in a single instrument that images a wide swath on the Earth's surface to advance aerosol remote sensing capabilities. MSPI is required to have 3% radiometric uncertainty and 0.005 degree of linear polarization (DoLP) uncertainty. These are difficult requirements that push the limits of available technologies needed to perform space-based polarimetric imaging. This work examines three topics related to MSPI fabrication and calibration: polarization errors and their correction, achromatic, athermal, quarter wave retarder fabrication, and analysis of a polarization state generator (PSG) for MSPI polarization calibration confirmation.MSPI polarization errors may arise from surface geometry of the optical components, coatings, and quarter wave plates (QWPs). Static polarization errors can be calibrated out, but result in decreased SNR. Polarization errors that drift following calibration cannot be corrected, so a sensitivity analysis is used to set time-varying diattenuation and retardance magnitude tolerances. QWPs are required to work in concert with the PEMs to modulate the linear component of the Stokes vector. A three-material achromatic, athermalized QWP was designed, fabricated and its performance validated. Analysis indicated that the compound QWP was unlikely to meet the requirements if plates were specified by thickness. To address this, a method for QWP fabrication was developed that involves monitoring retardance during polishing. To verify MSPI performance, a PSG was built and calibrated which outputs weakly linearly polarized light with DoLPs varying from 0.0005 to 0.4 with 0.0005 uncertainty by passing nearly unpolarized light through a tilted plane parallel plate. The PSG was intended to act as a calibration standard based on calculated DoLP, but proved difficult to model. Therefore, the DoLP was instead measured to repeatability of 0.0005. Finally, example spectropolarimetric image data taken with MSPI was presented. Work on a follow-on prototype continues that will advance the technologies needed to realize the space-based, fully capable MSPI.
Type:
text; Electronic Dissertation
Keywords:
Achromatic retarder; Polarimetry; Remote sensing
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Optical Sciences; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Chipman, Russell A.
Committee Chair:
Chipman, Russell A.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleMULTIANGLE SPECTROPOLARIMETRIC IMAGER (MSPI)en_US
dc.creatorMahler, Anna-Britten_US
dc.contributor.authorMahler, Anna-Britten_US
dc.date.issued2010en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractSubstantial impacts of aerosols on climate and public health underscore the need for accurate characterization of atmospheric aerosol distributions and microphysical properties. The Multiangle SpectroPolarimetric Imager (MSPI) combines accurate multispectral, multiangle, and polarimetric technologies in a single instrument that images a wide swath on the Earth's surface to advance aerosol remote sensing capabilities. MSPI is required to have 3% radiometric uncertainty and 0.005 degree of linear polarization (DoLP) uncertainty. These are difficult requirements that push the limits of available technologies needed to perform space-based polarimetric imaging. This work examines three topics related to MSPI fabrication and calibration: polarization errors and their correction, achromatic, athermal, quarter wave retarder fabrication, and analysis of a polarization state generator (PSG) for MSPI polarization calibration confirmation.MSPI polarization errors may arise from surface geometry of the optical components, coatings, and quarter wave plates (QWPs). Static polarization errors can be calibrated out, but result in decreased SNR. Polarization errors that drift following calibration cannot be corrected, so a sensitivity analysis is used to set time-varying diattenuation and retardance magnitude tolerances. QWPs are required to work in concert with the PEMs to modulate the linear component of the Stokes vector. A three-material achromatic, athermalized QWP was designed, fabricated and its performance validated. Analysis indicated that the compound QWP was unlikely to meet the requirements if plates were specified by thickness. To address this, a method for QWP fabrication was developed that involves monitoring retardance during polishing. To verify MSPI performance, a PSG was built and calibrated which outputs weakly linearly polarized light with DoLPs varying from 0.0005 to 0.4 with 0.0005 uncertainty by passing nearly unpolarized light through a tilted plane parallel plate. The PSG was intended to act as a calibration standard based on calculated DoLP, but proved difficult to model. Therefore, the DoLP was instead measured to repeatability of 0.0005. Finally, example spectropolarimetric image data taken with MSPI was presented. Work on a follow-on prototype continues that will advance the technologies needed to realize the space-based, fully capable MSPI.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectAchromatic retarderen_US
dc.subjectPolarimetryen_US
dc.subjectRemote sensingen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineOptical Sciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorChipman, Russell A.en_US
dc.contributor.chairChipman, Russell A.en_US
dc.contributor.committeememberTyo, J. Scotten_US
dc.contributor.committeememberFalco, Charlesen_US
dc.identifier.proquest11283en_US
dc.identifier.oclc752261126en_US
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