Integrating diffractive lenses (DLs) into optical imaging systems often significantly decrease their size or increase their performance. Despite only efficient for small diffraction angles, it is quantitavily shown that DLs are suitable for high-numerical-aperture systems. JCMsuite is used to simulate the diffraction properties in the limit of infinitely periodic structures.
D. Werdehausen, et al. Flat optics in high numerical aperture broadband imaging systems. Journal of Optics, 22(6), 065607 (2020).