Abstract
The JPSS-1 VIIRS instrument includes a number of spectral bands covering the wavelength range from 400 nm to 900 nm. Redesign of the spectral bandpass filters to reduce optical crosstalk observed on S-NPP VIIRS had the unexpected consequence of introducing larger polarization sensitivity in bluest bands on JPSS-1 VIIRS (between 400 nm and 600 nm). Additional testing as well as ray-trace modeling were performed to validate these large sensitivities. One of the additional tests performed used a monochromatic source (the T-SIRCUS provided by NIST) to both confirm the broadband measurements and validate aspects of the ray trace model. Limited measurements were collected for the spectral bands centered at 412 nm and 555 nm in terms of both wavelength and scan angles. Test data analysis has shown that the monochromatic and broadband measurements agree well in addition to confirming the findings from the ray trace model in that large diattenuation at the edges of the bandpass was driving the higher polarization sensitivity. Uncertainty analysis has shown that even with the limited measurements made, the monochromatic and broadband results are consistent. Additionally, the measurements were used to construct a spectrally dependent responsivity for each polarization state and to determine how certain spectral band characteristics change with polarization angle. Alternatively, the spectral band dependent diattenuation was determined from these polarization dependent responsivity functions.
Monochromatic Measurements of the JPSS-1 VIIRS Polarization Sensitivity
The JPSS-1 VIIRS instrument includes a number of spectral bands covering the wavelength range from 400 nm to 900 nm. Redesign of the spectral bandpass filters to reduce optical crosstalk observed on S-NPP VIIRS had the unexpected consequence of introducing larger polarization sensitivity in bluest bands on JPSS-1 VIIRS (between 400 nm and 600 nm). Additional testing as well as ray-trace modeling were performed to validate these large sensitivities. One of the additional tests performed used a monochromatic source (the T-SIRCUS provided by NIST) to both confirm the broadband measurements and validate aspects of the ray trace model. Limited measurements were collected for the spectral bands centered at 412 nm and 555 nm in terms of both wavelength and scan angles. Test data analysis has shown that the monochromatic and broadband measurements agree well in addition to confirming the findings from the ray trace model in that large diattenuation at the edges of the bandpass was driving the higher polarization sensitivity. Uncertainty analysis has shown that even with the limited measurements made, the monochromatic and broadband results are consistent. Additionally, the measurements were used to construct a spectrally dependent responsivity for each polarization state and to determine how certain spectral band characteristics change with polarization angle. Alternatively, the spectral band dependent diattenuation was determined from these polarization dependent responsivity functions.