DIFFERENTIAL INTERFERENCE CONTRAST FOR X-RAY MICROSCOPY: FABRICATION AND CHARACTERIZATION OF TWIN ZONE PLATE OPTICS

Abstract

A novel X-ray technique for converting the phase information of weakly absorbing specimen into strong image contrast similar to Nomarski differential interference contrast (DIC) is presented. DIC for X-rays is accomplished by the fabrication of a novel X-ray optic (TZP) consisting of two zone plates (ZPs) on both sides of the same substrate, laterally shifted by about one outermost zone width. The feasibility of DIC for X-rays was proven at the ID 21 X-ray microscopy beamline at the ESRF using a full-field imaging microscope and a scanning transmission X-ray microscope, which were operated at 4 keV photon energy. In both microscopes, we observe a tremendous contrast enhancement of up to a factor of 25. Though first experiments were carried out at 4 keV photon energy, this X-ray DIC technique can be adapted to any photon energy where ZPs with appropriate parameters and imaging performance can be designed and manufactured.