# Polarization Transmission of Visible Light in Inhomogeneous Sea Fog Particle Environment
## 4 Results and Discussion
### Experimental Results and Discussion  
The indoor simulation experiment results of the three wavelengths are shown in Figure 10. The three DOP curves overlap because the DOP difference of 0\({}^{\circ}\), 45\({}^{\circ}\), and 90\({}^{\circ}\) linearly polarized lights is less than 1%. For the polarized light of the three wavelengths, the DOP of the circularly polarized light and the linearly polarized light decreases with the increase of the optical thickness. Moreover, the difference between the DOP of circularly polarized light and that of linearly polarized light is approximately 30%. These DOP values are initially close. Circularly polarized light has better polarization-maintaining ability than linearly polarized light [20]. The measured data of 0\({}^{\circ}\), 45\({}^{\circ}\), and 90\({}^{\circ}\) linearly polarized lights and right-handed circularly polarized light of the three wavelengths are used to draw Figure 11. We can compare the change law of polarization characteristics under different wavelengths. In the visible band, the DOP decreases with the increase of the wavelength. DOP\({}_{450}\) is higher than DOP\({}_{532}\) by approximately 10%, and DOP\({}_{532}\) is higher than DOP\({}_{671}\) by approximately 15%. The measured results are close to the simulation results, and the change trend is consistent. Figure 10: Measured curves of DOP and optical thickness under different wavelengths: (**a**) \(\lambda=450\) nm; (**b**) \(\lambda=532\) nm; (**c**) \(\lambda=671\) nm. Figure 9: Relationship between DOP and optical thickness under different polarization states: (**a**) horizontal; (**b**) +45\({}^{\circ}\); (**c**) vertical; (**d**) right-handed rotation. The indoor simulation experiment results of the five relative humidity conditions are shown in Figure 12. DOP shows an upward trend with an increase in relative humidity. The relative humidity increases from 45% to 85%, and DOP increases by approximately 15%. The results are close to the simulation results, and the change trend is consistent. Figure 11: Measured curves of DOP and optical thickness for three wavelengths under different polarization states: (**a**) horizontal; (**b**) +45\({}^{\circ}\); (**c**) vertical; (**d**) right-handed rotation. Figure 12: Measured curves of DOP and optical thickness for five relative humidity conditions under different polarization state conditions: (**a**) horizontal; (**b**) +45\({}^{\circ}\); (**c**) vertical; (**d**) right-handed rotation. The accuracy of the inhomogeneous particle scattering model should be calculated. According to the following formula, we can calculate the accuracy [21]:  
\[M=1-(\sum_{1}^{n}\frac{|R-R_{m}|}{R_{m}})/n\times 100\% \tag{21}\]  
\(R\) and \(R_{m}\) are the polarization degree values obtained by the simulation and measurement at a certain sampling point, respectively. The accuracy calculation results of the inhomogeneous particle scattering model under different wavelength bands and relative humidity conditions are shown in Tables 5 and 6. Tables 5 and 6 show that under three visible light bands and five relative humidity conditions, the inhomogeneous particle scattering model has the lowest accuracy of 75.29% and the highest accuracy of 88.62%. Therefore, the actual measurement and simulation