X-ray microscopy is a mature characterization tool routinely used to answer various questions of science, technology and engineering. The high penetration power of X-rays allows to utilize different characterization methods and reveal elemental composition, crystalline phases, strain distribution, oxidation states etc. in macroscopic and microscopic samples. To obtain comprehensive chemical and structural information at the nanometer scale an X-ray microscope must be equipped with adequate capabilities and allow acquisition of multiple datasets simultaneously. Full-field or scanning X-ray microscopes usually serve this purpose and complement each other. In the recent years, a number of X-ray microscopes have been designed, constructed and commissioned at NSLS-II. In this work we provide an overview of the microscopy instrumentation developments at NSLS-II. It includes the multilayer Laue Lens based nanoprobe optimized for 10 nm spatial resolution imaging, it’s current status and future upgrades; the zone plate based full-field imaging system capable of nano-tomography measurements in less than 1 minute; a laser scanning system optimized for ptychography measurements along with algorithms development, and a new Kirkpatrick-Baez based scanning microscope designed for sub-100 nm spatial resolution experiments.
Hard X-ray microscopy is a powerful scientific tool capable of providing sub-10 nm spatial resolution imaging of material’s chemical composition and internal structure. Multilayer Laue Lenses (MLLs) have been developed and used for hard x-ray nanofocusing. MLLs are one dimensional X-ray diffractive optics fabricated through multilayer deposition and sectioning. An orthogonal alignment of two MLLs yields a point focus; 10 milli-degree orthogonality and sub-10 µm positioning accuracy along the beam direction is required to avoid astigmatism and achieve 10 nm focal spot size at 12 keV photon energy. Up-to-date, developed x-ray microscopy systems were equipped with eight degrees of nano-scale motion to perform full alignment of individual MLL optics. Bonding of two individual lenses together in pre-determined configuration significantly simplifies alignment process and makes them compatible with a more conventional Zone Plate – based microscopes. In this work, we give an overview of the existing bonding effort and present our approach to fabricate a monolithic 2D MLL optic.
With the progress of achieving diffraction-limited X-ray focus, ptychography offers a unique and powerful tool to provide quantitative reconstruction of the complex-valued wavefront of a focused beam. Propagation of the reconstructed wavefront essentially describes complete performance characterization of the optics. We will present the accumulated efforts at NSLS-II on exploring the capability of ptychography to quantify focusing performance of a variety of hard X-ray optics, including K-B mirrors, zone plates, multilayer Laue lenses [1-3]. Presentation will also elaborate on our recent development of monolithically bonded MLLs as a signal optical component for scanning probe microscope applications [4,5].
 X. Huang, et al., “Quantitative X-ray wavefront measurements of Fresnel zone plate and K-B mirrors using phase retrieval”, Optics Express, 20, 24038-24048 (2012).
 X. Huang, et al., “11 nm hard X-ray focus from a large-aperture multilayer Laue lens”, Scientific Reports, 3, 3562 (2013).
 X. Huang, et al., “Achieving hard X-ray nanofocusing using a wedged multilayer Laue lens”, Optics Express, 23, 12496-12507 (2015).
 E. Nazaretski, et al., “Development and characterization of monolithic multilayer Laue lens nanofocusing optics"”, Applied Physics Letters, 108, 261102 (2016).
 X. Huang, et al., “Hard x-ray scanning imaging achieved with bonded multilayer Laue lenses”, submitted, (2017).
Thermoelectric oxide nanofibers prepared by electrospinning are expected to have reduced thermal conductivity when compared to bulk samples. Measurements of nanofibers’ thermal conductivity is challenging since it involves sophisticated sample preparation methods. In this work, we present a novel method suitable for measurements of thermal conductivity in a single nanofiber. A microelectro-mechanical (MEMS) device has been designed and fabricated to perform thermal conductivity measurements on a single nanofiber. A special Si template was designed to collect and transfer individual nanofibers onto a MEMS device. Pt was deposited by Focused Ion Beam to reduce the effective length of a prepared nanofiber. A single La<sub>0.95</sub>Sr<sub>0.05</sub>CoO<sub>3</sub> nanofiber with a diameter of 140 nm was studied and characterized using this approach. Measured thermal conductivity of a nanofiber was determined to be 0.7 W/m•K, which is 23% of the value reported for bulk La<sub>0.95</sub>Sr<sub>0.05</sub>CoO<sub>3</sub> samples.