Polar decomposition of Mueller matrices for 2D-structured surfaces

Abstract

In this research, the Polar Decomposition (PD) has been applied to the Mueller matrices (MMs) of the light scattered by linear ribs of rectangular profile on a flat substrate. Although photo-lithographic technique produces a silicon surface, metallic character is acquired by sputtering with gold some of the samples. With a dual rotating compensator polarimeter the MMs are obtained by Fourier Transform analysis. The samples have been numerically modeled by using both FDTD and Extinction Theorem (ET) and MMs have been computed from the results. The scattering depends strongly on the geometry and composition of the ribs, and this sensitivity is noticed for instance in M11 element. But information offered by PD parameters is shown to be more apprehensible, like the substrate-induced depolarization or the retardance associated to the rib width.