The Advanced Photon Source (APS) and APS Users Organization (APSUO) are very pleased to announce that the 2005 Arthur H. Compton Award was given to Günter Schmahl and Janos Kirz for pioneering and developing the field of x-ray microscopy using Fresnel zone plates. Because of their leadership over the last 30 years, x-ray microscopy has evolved into a powerful method for the study of nanoscale structures and phenomena in many areas of science.
Their achievements have opened up productive research avenues in biology, polymers, electronic nanostructures, magnetic materials, meteoritics, and environmental sciences. “ Günter Schmahl and Janos Kirz have created a whole new field through persistent efforts over many years,” says Harald Ade of North Carolina State University. “The impact of their work will only keep growing as nanotechnology becomes more and more important.”
The key advance was the use of Fresnel zone plates to focus x-rays for either full-field imaging (Schmahl) or scanning microscopy (Kirz). Schmahl was among the first to develop Fresnel zone plates for the x-ray range (1969), based on his work on holographic manufacture of diffraction gratings (1967). He and his colleagues at the University of Göttingen built the first zone-plate-based full-field transmission x-ray microscope at DESY.
Kirz pursued a complementary direction with a similarly wide-ranging impact. In a seminal paper in 1974, he outlined the theoretical capabilies of diffractive optics in the extreme ultraviolet and x-ray regimes. Kirz’s group at the State University of New York at Stony Brook and colleagues at the Lawrence Berkeley National Laboratory pioneered methods for making high-resolution x-ray zone plates by electron beam lithography, in collaboration with researchers at IBM’s T.J. Watson Research Laboratory. Working at the National Synchrotron Light Source, his team incorporated these plates into the first scanning transmission x-ray microscopes achieving sub-micron resolution (1983).
The continuing work of both Schmahl and Kirz has had exceptionally wide impact, both in terms of optics hardware and scientific applications. Zone-plate lenses based on the processes developed by Kirz and colleagues now serve both soft and hard x-ray applications worldwide and are found not only at synchrotron x-ray sources but also in commercial laboratory instruments. Schmahl’s group at Göttingen extended the suite of x-ray microscopy techniques to include x-ray phase contrast, cryo-preparation of radiation-sensitive specimens, tomographic methods, and use of laboratory x-ray sources in full-field x-ray microscopes. Kirz and his colleagues and students have extended the capabilities of their instruments well into the nanometer region and developed ground-breaking methods for x-ray near-edge absorption spectroscopy, differential phase contrast microscopy, and coherent diffraction microscopy.
The full impact of these developments is still emerging. “ The field of synchrotron x-ray microscopy is expanding rapidly, in large part due to the key contributions Schmahl and Kirz have made,” says Adam Hitchcock of McMaster University. Many scientific programs based on full-field and scanning x-ray microscopes are thriving at synchrotron and laboratory facilities around the world. According to Ade, “ Few developments can boast such a range and depth of impact as the work of Schmahl and Kirz has had--and will continue to have.”
Key publications:
G. Schmahl and D. Rudolph, “Lichtstarke Zonenplatten als abbildende Systeme für weiche Röntgenstrahlen,” Optik 29, 577 (1969).
B. Niemann, D. Rudolph and G. Schmahl, “Soft X-ray imaging zone plates with large zone numbers for microscopic and spectroscopic applications,” Opt. Commun. 12, 160 (1974)
J. Kirz, “Phase zone plates for x rays and the extreme UV,” J. Opt. Soc. Am. 64, 301 (1974).