This Applied Optics article reports on the Visible Infrared Imaging Radiometer Suite (VIIRS) of JPSS-1, a satellite that is part of the Joint Polar Satellite System. The bands at the blue end of the spectrum show unexpectedly large polarization sensitivities (up to 6.4%, compared to the less than 3.0% for the similar instrument SNPP VIIRS). T-SIRCUS, a NIST device, was used for the test: SIRCUS uses continuously tunable lasers coupled into a 1 m diameter integrating sphere to provide a uniform spectral irradiance or radiance source at a 30 cm output port. A sheet polarizer was mounted in front of this exit port, realizing in this way a uniform source with variable polarization.
A Fourier analysis approach was used to calculate the Mueller matrix components of the VIIRS. The polarization measurements were performed for varying wavelength, the HAM (half angle mirror) side and the scanning angle for several different test types (scattered light, polarization efficiency or polarization sensitivity). A ray-tracing model showed that the cause for the unexpectedly large polarization sensitivity in the shortest wavelength bands is a difference in s and p polarization transmittance at the edges of the instrument’s input bandpass.
In summary, this article provides a comprehensive overview of the theoretical and experimental problems associated with the investigation of the polarization of multi- and hyperspectral systems. The readers of this article will now be looking forward to new research on how to handle the effects of self-polarisation in the data provided by this instrument.
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