Design and application of broadband and wide-angle double-layer diffractive optical element based on dual-objective optimization

This paper presents a dual-objective optimization method to tackle the low diffraction efficiency and high angular sensitivity of traditional double-layer diffractive optical elements (DLDOEs) in broadband and wide-angle scenarios. By developing a mean-standard deviation dual-objective diffraction efficiency evaluation model (MSDODE) and incorporating material library matching constraints based on dispersion characteristics, we achieve a globally coordinated optimization of DLDOE substrate material selection and microstructure height. The optimized design attains an average diffraction efficiency of 0.9614 within the 0.4∼1.0μm wavelength range and 0∼30° incident angle range, outperforming conventional designs. The average diffraction efficiency at 30° decreases by a mere 0.08% compared to that at 0°. When applied to a wide-spectrum annular-aperture lens (AFL) system, the design demonstrates excellent chromatic aberration correction, with the system modulation transfer function (MTF) exceeding 0.36 at 166lp/mm. The average MTF reduction due to diffraction efficiency impact is minimal, at just 0.045%.