Infrastructure and everyday materials

Imaging the hot turbulence of aircraft propulsion systems may now be possible with sturdy sheets of composite materials that twist light beams, according to researchers from the University of Michigan, the Air Force Research Laboratory, ARCTOS Technology Solutions (Beavercreek, OH), the Brazilian Center for Research in Energy and Materials in Campinas, Brazil, and the Federal University of São Carlos in Brazil. The key is arranging nanomaterials that don't twist light on their own onto layers that turn light waves into either left- or right-handed spirals, known as circular polarizations.

Researchers from North Carolina State University; Stanford University; the U.S. Department of Energy’s Lawrence Berkeley National Laboratory and SLAC National Accelerator Laboratory; and the University of Geneva have, for the first time, demonstrated that a specific class of oxide membranes can confine, or "squeeze," infrared light. The thin-film membranes (which are 100-nanometer-thick) confine infrared light far better than bulk crystals, which are the established technology for infrared light confinement.

Researchers from Rice University and the U.S. Department of Energy’s Oak Ridge National Laboratory have developed an additive-free, water-based ink made of lignin and cellulose, the fundamental building blocks of wood. The ink can be used to produce architecturally intricate wood structures via a 3D printing technique known as direct ink writing. The researchers focused on optimizing the composition of the ink by adjusting the ratio of lignin, cellulose nanofibers, and nanocrystals while maintaining the natural lignin-cellulose balance.

Researchers from the Massachusetts Institute of Technology, Universitat de Girona in Spain, and Universidade do Porto in Portugal have shown that they can prevent cracks from spreading between layers in a composite material by depositing chemically grown forests of carbon nanotubes between the composite layers. The tiny, densely packed fibers grip and hold the layers together, like ultrastrong Velcro, preventing the layers from peeling or shearing apart.

Researchers from Penn State have created a metasurface that can be used to preprocess and transform images before they are captured by a camera, allowing a computer – and artificial intelligence – to process them with minimal power and data bandwidth. A metasurface is an optical element akin to a glass slide that uses tiny nanostructures placed at different angles to control light. This new metasurface has many potential applications, including for use in target tracking and surveillance to map how a car, for example, moves across a city.

Researchers from Harvard University and Utrecht University in The Netherlands have developed a previously elusive way to improve the selectivity of catalytic reactions, adding a new method of increasing the efficacy of catalysts for a potentially wide range of applications in various industries, including pharmaceuticals and cosmetics.

Researchers from Yale University, the Korea Institute of Science and Technology, and the Chinese Academy of Sciences have reported new findings on the behavior of metallic glass and how these materials deform or respond to external stresses at very small size scales. Their finding of the size limits (approximately 100 nanometers) at which metallic glass does not deform provides insights that could lead to new ways of creating metallic glasses and provide researchers with a novel method to slowly grow metastable materials. 

Purdue University researchers have merged the power of advanced surfaces with thermal imaging algorithms to create a device that could open new frontiers in machine vision and autonomous systems. The device, called a Spinning MetaCam, could help classify materials and provide new possibilities for technologies in security, thermography, medical imaging, and remote sensing. The Spinning MetaCam contains metasurfaces – structured electromagnetic nanoscale surfaces crafted to behave like aqueducts for water, filtering and channeling light.

Researchers at Vanderbilt University have created a metasurface-based imager (meta-imager) that can potentially replace traditional imaging optics in machine-vision applications, producing images at higher speed and using less power. A metasurface is a thin material composed of arrays of subwavelength nanostructures. The nanostructuring of the material into the meta-imager filter reduces the typically thick optical lens and enables front-end processing that encodes information more efficiently.