Novel Holographic Spectroscopy for First Determination of Complex Atomic Fine Structure

X-ray Absorption Spectroscopy (XAS) is the mainstay for nanoscale structural studies of amorphous, crystalline, solid, and solution samples. However, X-ray Spectroscopy from phase lacks a spectroscopic measurement technique. We describe and implement novel holographic spectroscopy for the first simultaneous determination of both the amplitude (absorption) and phase spectra, which together we refer to as the Complex Atomic Fine Structure (CAFS). This pioneering work lays the foundation for X-ray Phase Spectroscopy and X-ray CAFS which enables the application of X-ray Spectroscopy to a wide range of low absorbing samples such as ultra-thin films, functional and bio-materials, and for studying material structure at the nano-scale. Our first results explicitly measure CAFS around the K-edges of copper and iron. The precision of the results is excellent, with a very well-defined oscillatory structure in both absorption and phase. Both phase and amplitude are in good agreement with published literature, yet their simultaneous measurement reveals new science and challenges. This raises important questions about new structural information in the phase of CAFS hitherto unseen and unknown. The new technique opens exciting opportunities for X-ray spectroscopy, promising a new tool for structural studies of low-absorbing samples, nanostructures, thin films, functional materials, and biological samples. It is well-suited as a diagnostic to give new insight for development and building of nanomaterials, and for advanced physics and chemistry for molecules and solids, crystalline or non-crystalline. It has impact on nanochemistry, biochemistry and nanoengineering. We discuss major consequences and opportunities for future growth.