Phys.org October 3, 2022 Researchers in Israel have shown that by using 3D-direct laser writing, high-quality optical devices could be fabricated directly on top of the fiber’s facet by the two-photon absorption process. They demonstrated how a high-order Bessel beam carrying orbital angular momentum could be generated by using this lithography process. The beam is shaped using an integrated micro-optical system that consists of a twisted axicon and parabolic lens in an adapted fiber configuration. They provided the analysis and measurements of the generated beam, along with simulated predictions. They found that the size of the central ring remained nearly […]
Researchers unveil mystery inside lithium oxygen batteries
Phys.org September 30, 2022 Researchers in China prepared an integrated air electrode with highly ordered channels. They observed morphological composition and distribution of Li2O2 inside the real air electrode. The results showed that the toroidal Li2O2 was constrained by the channel size and exhibited a larger diameter on the separator side at high currents. The coupling effects of charge transfer impedance and concentration polarization on sudden death were analyzed in-depth at low and high currents. The growth model suggested that toroidal Li2O2 exhibited a high dependence on the electrode surface structure. They proposed a new route where the Li2O2/electrode interface […]
Reward research for being useful — not just flashy
Nature October 4, 2022 According to the author who oversaw basic research programs across the US Department of Defense, and other organizations, too many countries have built a research pipeline that venerates prizes and papers above all else. People and their problems get left out as scientists chase novelty and the prestige it brings. Too often the more applied a proposal is, the less likely it is to be funded. Even research funds intended for applied work reward novelty over utility. Long-term support for science might depend on scientists helping to solve local problems, such as the regional flooding, fires […]
Solar harvesting system has potential to generate solar power 24/7
Science Daily October 3, 2022 Traditional solar thermophotovoltaics (STPVs) rely on an intermediate layer to tailor sunlight for better efficiencies. However, the thermodynamic efficiency limit of STPVs is still far lower than the Landsberg limit (93.3%), the ultimate efficiency limit for solar energy harvesting. Researchers at the University of Houston showed that the efficiency deficit is caused by the back emission of the intermediate layer towards the sun resulting from the reciprocity of the system. They proposed nonreciprocal solar thermophotovoltaics (NSTPV) that utilize an intermediate layer with nonreciprocal radiative properties. Such a nonreciprocal intermediate layer could substantially suppress its back […]
Stretchy, bio-inspired synaptic transistor can enhance, weaken device memories
Science Daily October 3, 2022 A team of researchers in the US (Pennsylvania State University, University of Houston, Northwestern University, industry) has developed a stretchy, wearable synaptic transistor that works like neurons in the brain. They used stretchable bilayer semiconductor materials to fabricate the device, allowing it to stretch and twist while in use unlike the conventional transistors. The transistor is mechanically deformable and functionally reconfigurable, yet still retains its functions when stretched extensively. It can be integrated in robots or wearables and use artificial intelligence to send signals to some cells and inhibit others to enhance and weaken the […]
Team develops method for neural net computing in water
Phys.org September 29, 2022 Ions in water move slower than electrons in semiconductors, scientists think the diversity of ionic species with different physical and chemical properties could be harnessed for richer and more diverse information processing. A team of researchers at Harvard University developed a 16 × 16 array of new ionic transistors in an aqueous quinone solution. Each transistor features a concentric ring electrode pair with a disk electrode at the center. The electrodes in the solution provided the basis for the transistor operation. The ring pair electrochemically tunes the local electrolytic concentration to modulate the disk’s Faradaic reaction […]
Top 10 Science and Technology Inventions for the Week of September 30, 2022
01. Exotic electronic effect found in 2D topological material 02. Heat-resistant nanophotonic material could help turn heat into electricity 03. Lab grows macroscale, modular materials from bacteria 04. MIT engineers build a battery-free, wireless underwater camera 05. New nanocomposite films boost heat dissipation in thin electronics 06. Researchers create synthetic rocks to better understand how increasingly sought-after rare earth elements form 07. ‘Optical magic’: New flat glass enables optimal visual quality for augmented reality goggles 08. Quantum technology reaches unprecedented control over captured light 09. Optical encryption method based on single pixel imaging and metasurface holography 10. Scientists use modified […]
Exotic electronic effect found in 2D topological material
Phys.org September 26, 2022 When external or intrinsic parameters break symmetries, global properties of topological materials change drastically. While a rich variety of non-trivial quantum phases could in principle also originate from broken time-reversal symmetry, realizing systems that combine magnetism with complex topological properties is remarkably elusive. An international team of researchers (Germany, USA – UC Davis) demonstrated that giant open Fermi arcs are created at the surface of ultrathin hybrid magnets where the Fermi-surface topology is substantially modified by hybridization with a heavy-metal substrate. The interplay between magnetism and topology allows for control of shape and the location of […]
Heat-resistant nanophotonic material could help turn heat into electricity
Nanowerk September 22, 2022 A team of researchers in the US (University of Michigan, University of Virginia) has developed materials using destructive interference phenomenon to reflect infrared energy while letting shorter wavelengths pass through. Using pulsed laser, they deposited oxides of calcium and titanium oxides. Oxides made the material more durable, less likely to degrade at high temperature, and they could be more precisely layered. The material controlled the flow of infrared radiation and was stable at temperatures of 2,000 degrees Fahrenheit in air, a nearly twofold improvement over existing approaches. After testing they confirmed that the material worked as […]
Lab grows macroscale, modular materials from bacteria
Nanowerk September 22, 2022 Engineered living materials (ELMs) embed living cells in a biopolymer matrix to create materials with tailored functions. While bottom-up assembly of macroscopic ELMs with a de novo matrix would offer the greatest control over material properties, the ability to genetically encode a protein matrix that leads to collective self-organization is lacking. A team of researchers in the US (Rice University, Lawrence Berkeley National Laboratory, UC Berkeley) grew ELMs from Caulobacter crescentus cells that display and secrete a self-interacting protein. This protein formed a de novo matrix and assembled cells into centimeter-scale ELMs. Discovery of design and […]