Abstract

The absorption edges of important light elements (C,N,O) fall in the soft x-ray range. Consequently, with proper choice of the beam energy one can penetrate relatively thick specimens or ionize the core level of an atom on the surface. The recently commissioned soft x-ray undulator at the NSLS is a bright and tuneable source of 200800 eV radiation. Teams from the NSLS, Lawrence Berkeley Laboratory, IBM, the University of California at San Francisco, and the State University of New York-Stony Brook have been using it to develop several forms of microimaging, including scanning transmission microscopy, scanning photoemission microscopy, holography and diffraction. Coherently illuminated zone plates¹ are used to form microprobes for scanning and as a source of spherical reference waves in Fourier transform holography. Three of the instruments have achieved resolutions in the 5070 nm range. Applications in biology include the study of whole cells and organelles, while work in surface science is just beginning to address the important problems of radiation-sensitive heterogeneous materials.

© 1990 Optical Society of America