ADVANCED MATERIALS & PROCESSES | JULY/AUGUST 2024 9 By controlling the degree of atomic disorder to achieve the desired optical properties, the scientists anticipate developing crystals that enable advanced infrared imaging in low light conditions—useful for tasks such as improving the performance of autonomous vehicles driving at night. The material under study was a hexagonal crystal, barium titanium sulfide, which is known to have large optical anisotropy, although scientists did not know why. It took years of collaboration between the university researchers and various national labs, but the team finally figured it out. Using a combination of single crystal x-ray diffraction, solid-state nuclear magnetic resonance, and scanning transmission electron microscopy, the scientists found evidence of anisotropic atomic displacements of the titanium atoms in BaTiS3. These picoscale displacements happen in local clusters within the material, yet they exert a profound influence on global optical properties. wustl.edu. FLEXIBLE MIRROR FOR X-RAY MICROSCOPES A team of researchers from Nagoya University, Riken, and JTEC Corp., Japan, developed a mirror for x-rays that can be flexibly shaped, resulting in outstanding atomic level precision and increased stability. One challenge is that the small wavelength of x-rays makes them vulnerable to distortion from minor manufacturing flaws and environmental influences, creating wavefront aberrations that can limit image resolution. The team solved this problem by creating a mirror that can deform, adjusting its shape according to the detected x-ray wavefront. To optimize their mirror, the researchers looked at different piezoelectric materials and ultimately selected a single crystal of lithium niobate as their shape-changeable mirror. Single-crystal lithium niobate is useful in x-ray technology because it can be expanded and contracted by an electric field and polished to a highly reflective surface. This allows it to serve as both the actuator and the reflective surface, simplifying the device. The team found that their x-ray microscope exceeded expectations. Compared to the spatial resolution of conventional x-ray microscopy (typically 100 nm), the new technique has the potential to develop a microscope that provides a resolution roughly 10 times better because the aberration correction brings it closer to the ideal resolution. www.nagoya-u.ac.jp. X-ray microscopic images showing the higher resolution using the new deformable mirror. The le and right were obtained before and a er shape correction, respectively. Courtesy of Matsuyama lab, Nagoya University. STAY AHEAD OF YOUR PROFESSIONAL JOURNEY WITH ASM EDUCATION & TRAINING. EARN CEUs, ENJOY DISCOUNTS, NETWORK, AND LEARN FROM INDUSTRY EXPERTS. SCAN TO ENROLL TODAY Education
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