Dr. Stephan Werner (F-12) is recipient of Werner Meyer-Ilse Memorial Award

High-efficiency, three-dimensional diffractive lenses for x-rays experimentally realized for first time ever

Dr. Stephan Werner has been named this year's recipient of the prestigious Werner Meyer-Ilse Memorial Award. Dr. Werner has received his award at the 11th International Conference on X-ray Microscopy (XRM2012) in Shanghai, China. Werner's innovative doctoral research focused on the development and characterization of three-dimensional, nanostructured x-ray optics known as "on-chip stacked zone plates." In the future, this type of optics could be used for the precise nanometer focusing of synchrotron radiation. The fact that these zone plates allow very high spatial resolutions in the nanometer range for soft and hard x-rays represents a major step forward in this important area of research. By recognizing Werner's work, an international committee of experts has essentially confirmed that it considers this research an important contribution to the field of x-ray microscopy.

Stephan Werner, one of only two scientists whose work is being recognized, recounts his initial reaction to learning he had been named a recipient of the award. "To be honest, I was rather surprised that I won - most especially because I knew that a number of exceptional works had been nominated. Of course, I am thrilled that, because of this award my work has garnered a high degree of visibility among members of the international scientific community." The junior researcher award is given every two years as part of the internationally renowned x-ray radiation imaging conference series. Currently, the physicist is doing his post-doc at the HZB Institute for Soft Matter and Functional Materials.

Six years ago, Werner joined HZB's microscopy department as a Ph.D. student, successfully earning his doctoral title in 2010 for his work on the development of high-efficiency diffractive optics at the Humboldt University, Berlin. Whereas the light microscope makes use of conventional refraction lenses, x-ray microscopes use zone plates for examining and imaging specimens. To develop these kinds of optics, the 31-year-old physicist made use of nanostructuring processes. The required nanometer-precise technologies are still considered a major challenge for the researchers. "In order to be able to use volume diffraction effects in zone plates, we would need to produce three-dimensionally tilted zone plate structures. They require extremely high accuracies – currently, we are still in the process of working out their experimental realization," Werner explains.

The most important equipment used to fabricate this new kind of optics is an electron beam lithography system. With its help, the researchers are able to write nanostructures into appropriate high-precision photoresists. The HZB's own e-beam writer was purchased back in 2010 in order to allow for the generation of nanostructures for multiple applications – as, for example, for developing high-resolution zone plates, fabricating photonic crystals, and x-ray grating manufacturing. After the zone plates are "written", dry etching and electroplating are the standard processes used to fabricate the zone plate structures. Besides a higher resolution in the nanometer range, the development of this new generation of optics marks also an important step in the direction of confocal x-ray microscopy.