Fig. 1. Initial structure of equal area partition

Fig. 2. PSO optimization model of achromatic diffractive lens

Fig. 3. Normalized spectral PSF distributions. (a) Fresnel diffractive lens; (b) initial zone achromatic diffractive lens; (c) coding optimized achromatic diffractive lens

Fig. 4. MTF of two types of lenses. (a) Fresnel lens; (b) coding optimized achromatic lens

Fig. 5. Light path diagram of test system

Fig. 6. PSF of three types of lenses. (a) Fresnel diffractive lens; (b) initial zone achromatic diffractive lens; (c) coding optimized achromatic diffractive lens

Fig. 7. Defocus pinhole images of two lenses. (a) Fresnel diffraction lens; (b) coding optimized achromatic diffraction lens

Fig. 8. Resolution of three discrete wavelengths. (a) Coding optimized achromatic diffractive lens; (b) traditional Fresnel diffractive lens

Fig. 9. Resolution comparison. (a) Resolution of traditional Fresnel diffractive lens;(b) resolution of coding optimized achromatic diffractive lens