Material selection and corresponding optimal surface relief height for multilayer diffractive optical elements

We present a model based on refractive index difference analysis for optimization of material selection for multilayer diffractive optical elements (MLDOEs). From the proposed model, two important relationships are derived: the relationship between material selection and the maximum polychromatic integral diffraction efficiency of MLDOEs, and between material selection and the surface relief heights of MLDOEs. The new relationships are more comprehensive and reliable than those discussed in previous papers. A theoretical expression of the optimal surface relief heights of MLDOEs is also presented, and its correctness is demonstrated through a comparison with the results of enumeration optimization.