Atmospheric Polarization Imaging
We have developed a dual-field-of-view polarimetric spectral imager that can record polarization images in a full hemisphere or a narrow field, for looking at the polarization of skylight or a distant object, respectively. This effort is supported by the Air Force Office of Scientific Research. The instrument is deployed on a rooftop platform and collects data routinely through a wide range of conditions to study the variability of sky polarization as a function of cloud, aerosol, and underlying surface conditions.
- N. J. Pust and J. A. Shaw, “Wavelength dependence of the degree of polarization in cloud-free skies: simulations of real environments,” Opt. Express 20(14), 15,559-15,568 (2012).
- N. J. Pust, A. R. Dahlberg, M. J. Thomas, J. A. Shaw, “Comparison of full-sky polarization and radiance observations to radiative transfer simulations which employ AERONET products,” Opt. Express 19(19), 18602-18613, doi:10.1364/OE.19.018602 (2011).
- A. R. Dahlberg, N. J. Pust, and J. A. Shaw, “Skylight polarization measurements at Mauna Loa, Hawaii,” Opt. Express 19(17), 16008-16021, doi:10.1364/OE.19.016008 (2011).
- N. J. Pust and J. A. Shaw, "Digital all-sky polarization imaging of partly cloudy skies," Applied Optics 47 (in press for Dec. 2008).
- N. J. Pust and J. A. Shaw, "Dual-field imaging polarimeter using liquid crystal variable retarders," Applied Optics 45(22), 5470-5478 (2006).
The Atmospheric Polarization Imager (API) uses an astronomical-grade CCD camera to view the entire sky dome through two liquid crystal variable retarders to achieve a full-Stokes image in only a few tenths of a second (important for imaging a scene with moving clouds). The system has a switchable fisheye or telephoto front end.