Design and rigorous modelling of structured multilayer gratings for broadband applications in the visible spectrum

Rigorous modelling by electromagnetic diffraction theory is used to design the diffractive polarizing beam splitters (DPBS) and to reach the best compromise between fabrication, feasibility and optical quality of the optical device. We use two types of integration methods: the rigorous coupled-wave analysis (RCWA) and a finite element method (FEM), where the latter comprises an optimization algorithm to solve the inverse diffraction problem by applying the method of gradient descend to minimize an integral functional over the visible spectral range involving the desired diffraction efficiencies.