Polarization-Insensitive broadband achromatic inverse design method for high numerical aperture metasurfaces

In biomedical imaging, especially in cellular and single-molecule imaging, multi-wavelength imaging and high resolution are critical performance indicators. Traditional high numerical aperture (NA) optical systems can improve resolution, but chromatic aberration correction is complex and affects the practical application of the system. This research proposes an inverse design method based on multi-wavelength metasurfaces, using super-oscillation phase modulation technology to achieve precise control of light fields across different wavelengths while maintaining consistent unit structure. Based on this approach, we designed a metasurface with a numerical aperture (NA) of 0.8, which demonstrates a 3.9 % chromatic aberration tolerance across the 560–740 nm wavelength range, with a focal depth range of 3 to 4 times the wavelength. Building upon this, the structure was further optimized using the adjoint optimization method with the initial structure as a starting point, achieving a full field of view of 20°.Additionally, the structure exhibits polarization-insensitive characteristics. This inverse design method provides a novel solution for chromatic aberration elimination and resolution enhancement in multi-wavelength optical systems, advancing metasurface technology towards practical applications.