Soft X-Ray Optics

Excerpt

This text describes optics mainly in the 10 to 500Å wavelength region. These wavelengths are 50 to 100 times shorter than those for visible light and 50 to 100 times longer than the wavelengths of medical x rays or x-ray diffraction from natural crystals. There have been substantial advances during the last 20 years, which one can see as an extension of optical technology to shorter wavelengths or as an extension of x-ray diffraction to longer wavelengths. Artificial diffracting structures like zone plates and multilayer mirrors are replacing the natural crystals of x-ray diffraction. Some of these structures can now be fabricated to have diffraction-limited resolution. We will try to describe the new possibilities in a simple, tutorial way. The basic optical theories are the same for soft x rays as for any other region of the electromagnetic spectrum. Several chapters of the book represent a concentrated overview of topics in general optics that are of importance for soft x rays. There are other textbooks that give a much more detailed and rigorous description of these fields. Our goal is a simple description that provides the intuition for an understanding of the basic principles. The optics of multilayer x-ray mirrors is described in greater detail, warranted by the great amount of research and recent progress in the fabrication, characterization, understanding, and application of multilayer x-ray mirrors.

This tutorial is based on numerous courses on x-ray optics that I have given during the last decade, beginning at the University of Rochester and continuing at the annual meetings of SPIE in San Diego. The Proceedings of the NATO School on the Physics, Fabrication, and Application of Multilayered Structures (Plenum Press, 1987) contain lecture notes that one can see as a precursor to the related chapters in this book.

I thank the IBM company for supporting me in a joint program with the Smithsonian Astrophysical Observatory in x-ray astronomy for more than a decade. Over the years I have had discussions with many people and have learned from them. I am especially indebted to T. W. Barbee, F. Christensen, E. Church, L. Golub, E. Gullikson, A. Hawryluk, W. Hunter, J. Kirz, J. Kortright, A. Rosenbluth, R. Schlatmann, and D. Stearns for providing data from their work prior to publication and for discussions of many topics of this text.