X-ray Linear Dichroism Microscopy.

Chemical-specific x-ray linear dichroism was observed in an x-ray microscope as evidenced by changes in relative contrast upon azimuthal rotation of the sample. As a demonstration, thin sections of a partially ordered polymer fiber were examined with a transmission x-ray microscope near the carbon K-shell absorption edge to provide chemical-specific imaging at 50-nanometer spatial resolution. The observed dichroism and change in contrast upon rotation arise from the polarization dependence of the near-edge x-ray absorption cross section and can be used to image the orientation of specific chemical bonds.