Retardance characteristics analysis of lens in polarization remote sensors

The polarimetric accuracy of existent polarization remote sensors is largely controlled by the polarization properties of those instruments themselves. The retardance of lens in the polarization remote sensors is a key part of the polarization characteristics whose stabilities are crucial for finally reliable polarimetric results. By analyzing the effect of the retardance of the lens in the polarimetric remote sensing measurement, it can show that the total retardance equals to the simple summing of each retardance from various optical interfaces with optical coatings, and the main part of total retardance is from optical coatings. The mathematical expression of retardance from single interface's broadband antireflection coatings is derived from thin film theoretical analysis. Typical examples of visible and near- infrared, infrared, ultra-broadband antireflection coatings in actual applications were studied with this expression, the result shows that retardance of general broadband antireflection coatings is monotone decreasing while wavelength increases. Furthermore, the lens in broadband polarization remote sensors can hardly achieve lower overall retardance by compensation between optical interfaces.