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3D-printed ‘plug’ links fiber optics to photonic chips with low loss

Physicists and chemists at Heidelberg University have realized a photonic microchip that is driven by light just as easily as electronic components via a “plug.” Their development could serve as the basis for fast and cost-effective production of photonic integrated systems that are of great importance for implementing innovative computing and communications systems.

Prof. Dr. Wolfram Pernice of the Kirchhoff Institute for Physics headed up the research on this novel coupling concept for light-controlled chips. The results appear in the journal Science Advances.

Smart fluorescent molecules provide cheaper path to sharper microscopy images

Multiphoton microscopy is used in biomedical research to study cells and tissues. Today, so-called two-photon microscopy is used to study processes within cells, but the technique has limitations in terms of image resolution. Four-photon microscopy provides images with higher resolution. However, such instruments are very expensive and, when studying biological material, the powerful laser light required can damage samples.

“In this project, we have developed molecules to visualize molecular-level details and monitor processes using the more common two-photon microscopy technique. These molecules have the capacity to achieve higher resolution than with four-photon microscopy, although two-photon microscopy is used,” says the project coordinator Joakim Andréasson, Professor at the Department of Chemistry and Chemical Engineering at Chalmers University of Technology.

“In the long term, results from studies of this kind may provide new insights into diseases, pharmaceuticals and the very smallest building blocks of life.”

Catching light in air: Programmable Mie voids boost light matter interaction

Atomically thin semiconductors such as tungsten disulfide (WS2) are promising materials for future photonic technologies. Despite being only a single layer of atoms thick, they host tightly bound excitons—pairs of electrons and holes that interact strongly with light—and can efficiently generate new colors of light through nonlinear optical processes such as second-harmonic generation.

These properties make them attractive for quantum optics, sensing, and on-chip light sources. At the same time, their extreme thinness imposes a basic limitation: There is very little material for light to interact with. As a result, emission and frequency conversion are often weak unless the surrounding photonic environment is carefully engineered.

A study published in Advanced Photonics introduces a new way to address this challenge by reshaping not the two-dimensional material itself, but the space beneath it. The researchers demonstrate a hybrid platform in which a monolayer of WS2 is placed on top of nanoscale air cavities, known as Mie voids, carved into a high-index crystal of bismuth telluride (Bi2Te3). The work shows that these voids can strongly enhance light emission and nonlinear optical signals, while also allowing direct visualization of localized optical modes.

Quantum dynamics show ‘memory’ depends on whether states or observables evolve

An international group of researchers have investigated the role of memory in quantum systems and dynamics. Their findings show that a quantum process can appear memoryless from one perspective while retaining memory from another. The discovery opens new research avenues into quantum systems and technologies.

In classical physics, the concept of memory is well understood. If the future evolution of a system depends only on its present state, the process is said to be memoryless. On the other hand, if past states continue to influence future outcomes, the system has memory.

In quantum physics, however, this clarity has long been missing. Quantum systems can store and transmit information in ways that have no classical analog, and the act of measurement plays a fundamental role in the dynamics.

A rewritable DNA hard drive may help solve the growing data storage crisis

Around the world, scientists are exploring an unexpected solution to the growing data crisis: storing digital information in synthetic DNA. The idea is simple but powerful—DNA is one of the most compact, durable information systems on Earth. But one issue has held the field back. Once data is written into DNA, it can’t be changed.

Now, researchers at the University of Missouri are helping to solve that problem by transforming DNA from a one-time medium into a rewritable digital hard drive. Their research is published in the journal PNAS Nexus.

“DNA is incredible—it stores life’s blueprint in a tiny, stable package,” said Li-Qun “Andrew” Gu, a professor of chemical and biomedical engineering at Mizzou’s College of Engineering. “We wanted to see if we could store and rewrite information at the molecular level faster, simpler and more efficiently than ever before.”

First 3D reconstruction of the face of ‘Little Foot’ completed

Identified as the most complete Australopithecus fossil discovered to date, “Little Foot” was buried in sediments whose movement and weight caused fractures and deformations, making analysis of its skull—and more particularly its face—difficult. This anatomical region, which is essential for understanding the adaptations of our ancestors and relatives to their environment, has now been virtually reconstructed for the first time by a CNRS researcher and her British and South African colleagues. These are published in Comptes Rendus Palevol.

A comparative analysis of this reconstruction with several extant great apes and three other Australopithecus specimens reveals that the face of “Little Foot” is closer in terms of size and morphology to Australopithecus specimens from eastern Africa than to those from southern Africa. This finding raises questions about the relationships between these different populations and about the chronology of the evolutionary processes that reshaped the faces of these hominins, particularly the orbital region, which appears to have been subject to strong selective pressures.

The skull was first transported to the Diamond Light Source synchrotron (United Kingdom), where it was carefully digitized. The research team then virtually isolated the bone fragments using semi-automated methods and supercomputers. Their realignment resulted in a 3D reconstruction with a resolution of 21 microns. More than five years were required to complete this reconstruction.

Heavier hydrogen makes silicon T centers shine brighter for quantum networks

Quantum technologies, computers or other devices that operate leveraging quantum mechanical effects, rely on the precise control of light and matter. Over the past decades, quantum physicists and material scientists have been trying to identify systems that can reliably generate photons (i.e., light particles) and could thus be used to create quantum technologies.

One approach for generating photons relies on silicon color centers, such as the emerging T center. Color centers are defects or irregularities in the crystal structure of silicon characterized by a different arrangement of atoms.

The T center and other silicon color centers can emit light in the wavelength band that is already used by fiber-optic internet cables, which is desirable for the development of quantum networks and quantum communication systems.

National report supports measurement innovation to aid commercial fusion energy and enable new plasma technologies

To operate fusion systems safely and reliably, scientists need to monitor plasma fuel conditions and measure properties like temperature and density that can affect fusion reactions. Making these measurements requires specialized sensors known as diagnostics.

A new report sponsored by the U.S. Department of Energy (DOE) recommends increased investment in America’s fusion diagnostic capabilities, a critical new technology that could provide DOE and Congress with information to speed up the delivery of commercial fusion power plants.

The report was produced as part of the DOE’s 2024 Basic Research Needs Workshop on Measurement Innovation, sponsored by the DOE’s Office of Science’s Fusion Energy Sciences (FES) program. It was chaired by Luis Delgado-Aparicio, head of advanced projects at the DOE’s Princeton Plasma Physics Laboratory (PPPL), and co-chaired by Sean Regan, a distinguished scientist and the director of the Experimental Division at the University of Rochester’s Laboratory for Laser Energetics.

Laser-within-a-laser delivers MeV X-ray radiography in picoseconds

Lawrence Livermore National Laboratory’s National Ignition Facility (NIF) is the hottest place on Earth for the briefest of moments during an experiment. Now, it can be one of the brightest places thanks to the Advanced Radiographic Capability (ARC), NIF’s laser-within-a-laser. How this is possible and how it’s measured is detailed in a paper in Physics of Plasmas titled “Development and scaling of MeV X-ray radiography at NIF-ARC.”

“This paper is a culmination of 13 NIF experiments over five years of data gathering, analyzing experiments, modeling and refining diagnostics,” said LLNL physicist Dean Rusby, the paper’s first author. “We’re able to create and measure an MeV X-ray source that can’t be done anywhere else on Earth.”

Scientists unveil universal aging mechanism in glassy materials

“Glass” has a unique and distinct meaning in physics—one that refers not just to the transparent material we associate with window glass. Instead, it refers to any system that looks solid but is not in true equilibrium and continues to change extremely slowly over time. Examples include window glass, plastics, metallic glasses, spin glasses (i.e., magnetic systems), and even some biological and computational systems.

When a liquid is cooled very quickly—a process called quenching—it doesn’t have time to organize into a crystal but becomes stuck in a disordered state far from equilibrium. Its properties—like stiffness and structure—slowly evolve through a process called “aging.”

Now, a research team from the Institute of Theoretical Physics of the Chinese Academy of Sciences has proposed a new theoretical framework for understanding the universal aging behavior of glassy materials. The study is published in the journal Science Advances.

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