Resolution enhancement of photon sieve based on apodization

Photon sieve is a novel diffractive optical element modulating either amplitude or phase which consists of a great number of pinholes distributed appropriately over the Fresnel zones for the focusing and imaging of light. Photon sieve has the advantages of the diameter of pinholes beyond the limitation of the corresponding Fresnel zone width and the minimum background in the focal plane. Furthermore, photon sieve can be fabricated on a single surface without any supporting struts required unlike the Fresnel zone plate. Photon sieve can be used as EUV telescope for solar orbiter, space-based surveillance telescope operating at visible light, or other imaging components. Photon sieve can also be used as one of the promising lithographic tools for nanoscale science and engineering to obtain the lower cost, higher flexibility and better resolution. The approaches to enhancing imaging resolution of photon sieve are presented in detail. According to Fresnel-Kirchhoff diffraction theory, the diffractive field of photon sieve is described by means of the discrete fast Fourier transform algorithm. The related contents include the calculation of point spread function, the suppression of side lobes, the imaging bandwidth, the physical limit of resolution, and the diffraction efficiency. Imaging properties of photon sieve are analyzed on the basis of precise test.