Research and Experimental Verification of Atmospheric Polarization State in the Near-infrared Band

The study of atmospheric polarization is the prerequisite and foundation for polarization detection, polarization remote sensing, polarization imaging and other applications. Compared with the visible wavelength, the research on atmospheric polarization state in the near-infrared wavelength is relatively lagging behind. The existing literature is dominated by theoretical analysis and lacks experimental verification. In this paper, a short-wave infrared image sensor, an infrared lens, an infrared polarizer, an infrared filter, etc. are used to build a near-infrared atmospheric polarization measurement system, and the polarization state of the atmosphere in the near-infrared band of 900～1700 nm is measured in the whole sky under the sunny weather conditions. The results show that the atmosphere shows stable polarization patterns in the near-infrared band, in which the stability of the atmospheric polarization angle distribution is obviously better than that of the atmospheric polarization degree distribution; the atmospheric polarization patterns are in good agreement with the Rayleigh scattering characterization model, with 83% of the points in the whole sky area having a polarization angle error of less than 10°, and 79% of the points having a polarization degree error of less than 0.1, which makes it possible to predict the atmospheric polarization states in various directions effectively by relying on the Rayleigh scattering characterization model. In addition, the overall polarization of the atmosphere in the whole daytime area is not high, with an average value of 0.13, and only 0.1 at noon, which is different from the theoretical derivation and assumption of the previous literature, and the applicability of polarization filtering technology to the detection of daytime targets should be investigated in depth in the context of specific applications.