Abstract
X-ray multilayers (MLs) – layered synthetic one-dimensional periodic microstructures – are playing an important role in the exploitation of x-rays, particularly soft x-ray/extreme ultra violet (XUV) region of the electromagnetic spectrum. However, understanding basic physics of x-ray MLs and controlling atomic distribution (hence surface/interface) over atomic depth scales in these nano-structured ML systems are crucial for optimum performance of optical elements. In this talk I will present the current state-of-the art research directions in the area of physics (basic and applied) of x-ray ML optics. I will discuss surface/interface studies through representative results of different material combinations. The talk will also cover correlation of structural parameters with tunable properties of x-ray MLs suitable for a variety of applications using synchrotron radiation.The second part of the talk will focus to uncover the underlying mechanism of resonance principle in x-ray scattering technique for basic surface/interface science with high sensitivity and unique additional feature compared to conventional x-ray scattering. Conventional x-ray reflectivity (XRR) probes spatial electron density distribution (within sensitive limit) but not directly atomic composition of the layer. A novel approach will be addressed not only the possible solution to low contrast physics issue of XRR but also an innovative approach to combine structural with chemical analysis using a single resonant scattering technique known for depth resolving sensitivity. We predicted resonant x-ray scattering combines layer sensitivity of reflectivity technique with short-range structural sensitivity such as chemical composition surrounding the resonating atom of spectroscopic technique due to element specificity and contrast variation mechanism of resonance effect. The sensitivity of resonant scattering to the presence of different chemical species around the resonating atoms is analogous to using deuteration as marker in neutron reflectivity. Novel idea will be demonstrated through representative results of different types of basic surface/interface studies near Si L-edge and boron K edge using synchrotron radiation..
