X-Ray Focusing: How Small a Spot Can We Make and Use in X-Ray Experiments?
Chris Jacobsen
Department of Physics and Astronomy, Stony Brook University
X-ray focusing optics have made significant progress in recent years, with resolutions in the 15-30 nm range demonstrated for soft and hard x-ray optics. These experiments produce the finest focus of electromagnetic radiation of any wavelength. In this talk, I will consider some of the practical and fundamental issues involved in pushing to even higher resolution. What do the fundamentals of x-ray optical interactions say about focusing limits? What about practical fabrication challenges? What types of foci are in fact usable in x-ray experiments? (I.e., what fraction of energy is contained within the central focus spot in various scenarios?) How can one measure the resolution? What types of specimen can survive what types of foci? Most of these will remain as questions raised rather than issues conclusively settled, but excitement at the prospects for ultimate limits must be tempered with realization of the challenges involved in reaching these limits.
