Default Polarization plots are automatically generated for Periodic ports in 3D and in 2D, if the Electric field components for setting in the Components section for the physics interface is set to Three-component vector. The Polarization plot includes polarization ellipses for each diffraction order. The polarization ellipse line graphs are generated by plotting the in-plane Jones vector element versus the out-of-plane Jones vector element for a phase change of 2π.