Hard x-ray phase zone plate fabricated by lithographic techniques

A Fresnel phase zone plate with an unprecedented focusing efficiency of 33% was fabricated using an x-ray lithographic technique and was tested using synchrotron x rays. Contributions by the zeroth-order x ray to the focus were minimal. Spatial resolution in the micrometer range was achieved. The measured spot size was dominated by geometric demagnification of the source. It should be possible to obtain submicrometer resolution by aperturing the source. Experimental results of focusing efficiency measurements, intensity distribution at the focal plane, and spatial resolution tests are reported.