Apodized photon sieves for phase-contrast nano-imaging of living cells

Abstract

We present a type of diffractive lenses "Zernike apodized photon sieves" (ZAPS), which structure is based on the combination of two concepts: apodized photon sieves and Zernike phase-contrast. In combination with the synchrotron light sources, the ZAPS can be used as an objective for high-resolution X-ray phase-contrast microscopy in physical and life sciences. The ZAPS is a single optic that integrates the appropriate ±π/2 radians phase shift through selective zone placement shifts in an apodized photon sieve. The focusing properties of the ZAPS can be easily controlled by apodizing its pupil function. An apodized photon sieve with Gaussian pupil was fabricated by lithographic technique and showed that the side-lobes have been significantly suppressed at the expense of slightly widening the width of the main lobe.