Broadband achromatic multilevel diffractive lens at visible frequency

We designed a broadband achromatic multilevel diffractive lens which is using the nanoparticle composite. Nanoparticle composite is a new artificial material, which has both pattern-transfer capability and high refractive index requirements. The device has good achromatic performance and good focusing performance at the focal plane in the visible band. The simulated average focusing efficiency is over 85% at the visible frequency.