First results from a dual photoelastic-modulator-based polarimetric camera.

We report on the construction and calibration of a dual photoelastic-modulator (PEM)-based polarimetric camera operating at 660?nm. This camera is our first prototype for a multispectral system being developed for airborne and spaceborne remote sensing of atmospheric aerosols. The camera includes a dual-PEM assembly integrated into a three-element, low-polarization reflective telescope and provides both intensity and polarization imaging. A miniaturized focal-plane assembly consisting of spectral filters and patterned wire-grid polarizers provides wavelength and polarimetric selection. A custom push-broom detector array with specialized signal acquisition, readout, and processing electronics captures the radiometric and polarimetric information. Focal-plane polarizers at orientations of 0 degrees and -45 degrees yield the normalized Stokes parameters q=Q/I and u=U/I respectively, which are then coregistered to obtain degree of linear polarization (DOLP) and angle of linear polarization. Laboratory test data, calibration results, and outdoor imagery acquired with the camera are presented. The results show that, over a wide range of DOLP, our challenging objective of uncertainty within +/-0.005 has been achieved.

[1]  B. Lamouroux,et al.  Automatic measurement of the Stokes vector of light. , 1979, Applied optics.

[2]  A. Drake.  Polarisation modulation-the measurement of linear and circular dichroism , 1986 .

[3]  S. Jasperson,et al.  An improved method for high reflectivity ellipsometry based on a new polarization modulation technique [Rev. Sci. Instrum. 40, 95 (1969)] (Errata) , 1969 .

[4]  Brian Cairns,et al.  Dual-photoelastic-modulator-based polarimetric imaging concept for aerosol remote sensing. , 2007, Applied optics.

[5]  P. Levelt,et al.  Aerosols and surface UV products from Ozone Monitoring Instrument observations: An overview , 2007 .

[6]  Anna-Britt Mahler,et al.  Minimizing instrumental polarization in the Multiangle SpectroPolarmetric Imager (MSPI) using diattenuation balancing between the three mirror coatings , 2008, Astronomical Telescopes + Instrumentation.

[7]  Baoliang Bob Wang,et al.  Stokes polarimeter using two photoelastic modulators , 2002, SPIE Optics + Photonics.

[8]  Olga V. Kalashnikova,et al.  Ability of multiangle remote sensing observations to identify and distinguish mineral dust types : Optical models and retrievals of optically thick plumes : Quantifying the radiative and biogeochemical impacts of mineral dust , 2005 .

[9]  J. Muller,et al.  The value of multiangle measurements for retrieving structurally and radiatively consistent properties of clouds, aerosols, and surfaces , 2005 .

[10]  Russell A. Chipman,et al.  Low polarization optical system design , 2007, SPIE Optical Engineering + Applications.

[11]  O. V. Kalashnikova,et al.  The ability of multi-angle remote sensing observations to identify and distinguish mineral dust types : Part 1 . Optical models and retrievals of optically thick plumes , 2004 .

[12]  Paul Ginoux,et al.  A Long-Term Record of Aerosol Optical Depth from TOMS Observations and Comparison to AERONET Measurements , 2002 .

[13]  Marcia J. Lebofsky,et al.  The infrared polarization of NGC 1275, NGC 4151, Markarian 231, and 3C 273 , 1977 .

[14]  M. Lebsock,et al.  Information content of near‐infrared spaceborne multiangular polarization measurements for aerosol retrievals , 2007 .

[15]  W. Grant,et al.  Stress plate optical modulator for circular dichroism measurements. , 1969, Applied optics.

[16]  James C. Kemp.  Photoelastic-Modulator Polarimeters In Astronomy , 1982, Optics & Photonics.

[17]  Christoph U. Keller,et al.  Astrophysical Spectropolarimetry: Instrumentation for Astrophysical Spectropolarimetry , 2001 .

[18]  W. Steen.  Absorption and Scattering of Light by Small Particles , 1999 .

[19]  E. Vermote,et al.  The MODIS Aerosol Algorithm, Products, and Validation , 2005 .

[20]  Georectification of the airborne multi-angle imaging spectroradiometer , 2001 .

[21]  Jia Zong,et al.  MISR in-flight camera geometric model calibration and georectification performance , 2002, IEEE Trans. Geosci. Remote. Sens..

[22]  Jochen Landgraf,et al.  Retrieval of aerosol properties over land surfaces: capabilities of multiple-viewing-angle intensity and polarization measurements. , 2007, Applied optics.

[23]  Kathleen A. Crean,et al.  Multiangle imaging spectroradiometer (MISR) global aerosol optical depth validation based on 2 years of coincident Aerosol Robotic Network (AERONET) observations : Global aerosol system , 2005 .

[24]  Maurice Herman,et al.  Aerosol remote sensing from POLDER/ADEOS over the ocean: Improved retrieval using a nonspherical particle model , 2005 .

[25]  Yoram J. Kaufman,et al.  Monitoring of aerosol forcing of climate from space: analysis of measurement requirements , 2004, Journal of Quantitative Spectroscopy and Radiative Transfer.

[26]  Bernard Pinty,et al.  Multi-angle Imaging SpectroRadiometer (MISR) instrument description and experiment overview , 1998, IEEE Trans. Geosci. Remote. Sens..

[27]  Peter R. J. North,et al.  Aerosol optical depth and land surface reflectance from multiangle AATSR measurements: global validation and intersensor comparisons , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[28]  Russell A. Chipman,et al.  Tolerancing and alignment of a three-mirror off-axis telescope , 2007, SPIE Optical Engineering + Applications.

[29]  J. Stenflo.  Solar magnetic and velocity-field measurements: new instrument concepts; errata. , 1984, Applied optics.

[30]  Brian Cairns,et al.  Case Studies of Aerosol Retrievals over the Ocean from Multiangle, Multispectral Photopolarimetric Remote Sensing Data , 2002 .

[31]  Beat Schmid,et al.  Polarimetric remote sensing of aerosols over land , 2009 .

[32]  Norman L. Thomas,et al.  UV-shifted durable silver coating for astronomical mirrors , 2000, Astronomical Telescopes and Instrumentation.

[33]  James C. Kemp,et al.  Piezo-Optical Birefringence Modulators: New Use for a Long-Known Effect , 1969 .