Development of a Polarization Scattering and Emission Model and a Simulation Software Based on the Physical Optics Approach

Current simulations (such as AFRL's) of optical polarization scattering and emission for remote sensing applications employ geometric optics. The approach is mathematically simple but lacks soundness of physics as it relies upon artificial adjustment ofpolarized specular and unpolarized diffuse components in the scattered radiation to match experiments. To significantly enhance AFRL's capability for polarization modeling and simulation, we propose to develop, during the Phase I and Phase II, a vector Kirchhoff diffraction integral model for polarization scattering and emission and to develop a fullsimulation code for target polarization modeling which includes atmospheric and environmental backgrounds. The vector Kirchhoff diffraction model will simulate a main lobe and a diffraction pattern for each rough surface facet of a material. Predicted measured polarization states will be result through calculating the diffraction lobes of different facetorientations. The Kirchhoff approach will produce specular and diffuse components solely depending on surface characteristics and incident/scattering angles. The primary Phase I objective is development of rough surface polarization scattering and emission models using the physical optics approach. A prototype simulation code for generating the scattering and emission polarization signatures for various targetsurface materials will be written and results compared to available experimental results. The result of this effort will enable us to understand the basic physics of the interaction between the incident (and emitted) radiation and the rough surface andwill significantly enhance the current AFRL capability for polarization modeling and simulation. It will provide a theoretical framework for efficient lab measurements of Mueller matrices of various target and environmental surface materials. This willprovide an essential part in simulation of the polarization of targets and backgrounds. The successful result of this work will also provide a systems engineering tool for developing polarimetric sensors and for the detailed optimization of data collectionplanning. This proposed work is directly applicable to the development of multispectral and hyperspectral imaging polarimeters. As these polarimeters come on line for military and commercial remote sensing, there is an increasing need for a capability tomodel target and background spectral polarization signatures. There is therefore a growing commercial market for a robust modeling capability.