The authors present an integrated acousto-optic modulator fabricated in a wafer-scale process that realizes efficient, high-speed modulation of visible light with high optical power handling.
Category: energy
Graphene membranes offer efficient, low-cost option for industrial CO₂ capture
Carbon capture is becoming essential for industries that still depend on fossil fuels, including the cement and steel industries. Natural-gas power plants, coal plants, and cement factories all release large amounts of CO₂, and reducing those emissions is difficult without dedicated capture systems. Today, most plants rely on solvent-based systems that absorb CO₂, but these setups use a lot of heat, require major infrastructure, and can be costly to run.
A smaller, electricity-driven alternative is what the field calls a “membrane” system. A membrane works like an ultra-fine filter that lets certain gases slip through more easily than others, separating CO₂ from the rest of the flue gas. The problem is that many membranes lose efficiency when CO₂ levels are low, which is common in natural-gas plants, and this limits where they can be used.
A new study at EPFL has now analyzed how a new membrane material, pyridinic-graphene, could work at scale. This is a single-layer graphene sheet with tiny pores that favor CO₂ over other gases. The researchers combined experimental performance data with modeling tools that simulate real operating conditions, such as energy use and gas flow. They also explored a wide range of cost scenarios to see how the material might behave once deployed in commercial plants.
Dual substitution induces room-temperature ferromagnetism and negative thermal expansion in BiFeO₃
Using a dual-cation substitution approach, researchers at Science Tokyo introduced ferromagnetism into bismuth ferrite, a well-known and promising multiferroic material for next-generation memory technologies. By replacing ions at both the bismuth and iron sites with calcium ions and heavier elements, they modified the spin structure and achieved ferromagnetism at room temperature. Additionally, negative thermal expansion was observed. This ability to engineer magnetism and thermal expansion in a multiferroic material aids in realizing future memory devices.
Multiferroic materials, which show both ferroelectricity and ferromagnetism, hold strong potential for use in low-power memory devices where information can be written electrically and read magnetically. Among these materials, bismuth ferrite (BiFeO3) is one of the most widely studied because it combines ferroelectricity with antiferromagnetism at room temperature.
However, BiFeO3 naturally forms a cycloidal spin structure, which is a wave-like pattern of rotating spins. This pattern cancels out any net magnetization and makes the material difficult to use in magnetic devices.
Radiofrequency upgrades ensure accelerator stability and reliability
Running a synchrotron light source is a massive team effort that brings hundreds of highly skilled and specialized professionals together. The radiofrequency (RF) group at the National Synchrotron Light Source II (NSLS-II), a U.S. Department of Energy (DOE) Office of Science user facility at DOE’s Brookhaven National Laboratory, plays an integral role in synchrotron operations. The work they do, often behind the scenes, ensures that the electron beam that enables cutting-edge science at NSLS-II remains bright, powerful, and stable.
The electrons that circle through NSLS-II’s nearly half-mile-long storage ring lose energy as they produce X-rays, which scientists use to perform a variety of experiments at the facility. To keep the beam moving steadily, the electrons pass through hollow RF cavities. These cavities, tuned to a precise frequency, restore the electrons’ energy each time they pass through.
When cooled to cryogenic temperatures, the material that the cavities are comprised of, niobium, takes on superconducting properties that nearly eliminate electrical resistance and drastically improve energy efficiency and beam stability. The design also allows unwanted high-frequency oscillations to be safely damped, ensuring a stable, high-intensity X-ray beam.
Reddit field experiment examines what distinguishes lurkers from power users
Online discussions are often dominated by a small group of active users, while the majority remain silent. This imbalance can distort perceptions of public opinion and fuel polarization.
In a group-based field experiment on Reddit, researchers from the Max Planck Institute for Human Development, TU Dresden, and Stanford University have investigated why some people remain silent readers (“lurkers”) while others are particularly active (“power users”)—and which measures might encourage people to join the discussion.
Results from the experiment are published in the journal Science Advances.
Humanity’s infinite energy solution might be in space
The full structure, if it is ever built, will likely take centuries. But the first pieces could be deployed within the next hundred years. Like the construction of cathedrals or transcontinental railroads, this is the kind of project that begins with a vision and takes shape slowly, across generations.
A Dyson sphere is not only about energy. It is about how we think. It challenges us to plan at the scale of a civilization rather than a single generation. It asks what kind of future we are trying to build, and whether we are willing to imagine a world of abundance rather than scarcity. It may take centuries to complete, but the mindset that makes it possible can start right now.
A new traveling-wave Josephson amplifier with built-in reverse isolation
Traveling-wave parametric amplifiers (TWPAs) are electronic devices that boost weak microwave signals (i.e., electromagnetic waves with frequencies typically ranging between 1 and 100 GHz). Recently, many engineers have been developing TWPAs based on superconductors, materials that conduct electricity with a resistance of zero at low temperatures.
Superconductor-based TWPAs can process signals with high efficiency, typically adding little noise to amplified signals. However, conventional amplifier designs lack directionality, which essentially means that electromagnetic energy can propagate backward towards the input, adversely impacting their performance.
Researchers at University Grenoble Alpes, CNRS, Silent Waves and Karlsruhe Institute of Technology recently developed a new TWPA based on nanoscale superconducting components known as Josephson junctions. This device, introduced in a paper published in Nature Electronics, can shift backward-traveling waves to higher frequencies, preventing the backward propagation that typically degrades the performance of TWPAs.
Durable catalyst shields itself for affordable green hydrogen production
An international research team led by Professor Philip C.Y. Chow at The University of Hong Kong (HKU) has unveiled a new catalyst that overcomes a major challenge in producing green hydrogen at scale. This innovation makes the process of producing oxygen efficiently and reliably in the harsh acidic environment used by today’s most promising industrial electrolyzers.
Spearheaded by Ci Lin, a Ph.D. student in HKU’s Department of Mechanical Engineering, the team’s work was published in ACS Energy Letters.
Green hydrogen is seen as a clean fuel that can help reduce carbon emissions across industries like steelmaking, chemical production, long-distance transportation, and seasonal energy storage. Proton exchange membrane (PEM) electrolyzers are preferred for their compact design and rapid response, but they operate in acidic conditions that are exceptionally demanding on the oxygen evolution reaction (OER) catalyst.
Blue jean dye could make batteries greener
Sustainability is often described in shades of green, but the future of clean energy may also carry a hint of deep blue. Electric vehicles and energy storage systems could soon draw power from a familiar pigment found in denim.
Concordia researchers have found that indigo, the natural dye used to color fabrics for centuries, can help shape the future of safe and sustainable batteries. In a study published in Nature Communications, the team revealed that the common substance supports two essential reactions inside a solid-state battery at the same time. This behavior helps the battery hold more energy, cycle reliably and perform well even in cold conditions.
“We were excited to see that a natural molecule could guide the battery chemistry instead of disrupting it,” says Xia Li, the study’s lead author and associate professor in the Department of Chemical and Materials Engineering. “Indigo helps the battery work in a very steady and predictable way. That is important if we want greener materials to play a role in future energy systems.”