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Category: nanotechnology

Metamaterials enable control of heat transfer at nanoscale, potentially transforming energy and electronics

Heat behaves in predictable ways: a hot cup of coffee cools, a laptop warms your hands, the sun heats Earth. But at scales thousands of times smaller than a human hair, those rules begin to break down, and scientists are learning how to take advantage of that.

A new study, published in Nature from researchers at Carnegie Mellon University, in collaboration with Stanford University and Purdue University, shows that heat can be manipulated far more powerfully than previously demonstrated using carefully engineered metamaterials. The work offers one of the clearest experimental confirmations yet that heat transfer can be actively designed and enhanced.

At the core of the discovery is a phenomenon called near-field radiative heat transfer. When two objects are brought extremely close together—just a few hundred nanometers apart—heat doesn’t simply radiate away in the usual sense. Instead, it can tunnel across the gap through electromagnetic waves, dramatically increasing how much energy flows between them.

Memory-preserving transistors could bypass the Boltzmann limit

Researchers have created a new theoretical framework that shows how memory-preserving “memtransistors” could overcome the intrinsic limits in efficiency faced by conventional semiconductor transistors, imposed by the laws of thermodynamics.

Led by Victor Lopez-Richard at the Federal University of São Carlos, Brazil, in collaboration with the University of Wurzburg, in Germany, and the University of Richmond, U.S., the researchers showed that further improvements to transistor switching efficiency could be reached simply by harnessing memory effects that are already present in many nanoscale devices. The research has been published in Physical Review Applied.

Prof. RHO Jun-seok Advances Metalens Technology from Manufacturing to Display Applications in Two Nature Papers

Nanoprinting imprinting metalenses 100x faster than lithography.

Professor RHO Jun-seok from the Departments of Mechanical Engineering and Chemical Engineering at POSTECH has gained international attention for developing a mass-production process for metalenses and a switchable 2D-3D display technology based on them. The two studies were simultaneously published in the April 30 issue of Nature. This marks the first case in Korea of a researcher publishing two separate papers as corresponding author in the same issue of the journal.

A metalens is a flat optical device that controls light using nanoscale structures rather than curved glass. By replacing bulky glass lenses with engineered surface patterns, optical systems become far thinner and lighter. Because this enables control of light at scales smaller than its wavelength, metamaterials are often regarded as a Nobel Prize–worthy field of research.

The first study addressed a key barrier to commercialization: large-scale manufacturing. Production has so far relied on expensive and complex semiconductor fabrication processes due to the extreme precision required, making it slow, costly, and largely limited to laboratory research. To overcome this, Prof. RHO’s team developed a Roll-to-Roll Nanoimprint process enabling continuous production using a cylindrical roller. Instead of fabricating nanoscale structures one by one on rigid molds, flexible polymer molds were used to imprint patterns onto thin films. This shifts fabrication from a one-at-a-time process to continuous factory-scale production. The team produced over 300 metalenses per second, about 100 times faster than conventional methods, while maintaining consistent performance over a 200-meter process.

Low-power, flexible radio-frequency transistors break 100 GHz barrier

Over the past decades, electronics engineers worldwide have been trying to develop devices that could enable even faster communications between devices, all while consuming less energy. To meet the demands of the sixth generation (6G) of wireless communication technology, these devices should operate at frequencies above 100 gigahertz (GHz).

So far, developing flexible electronic components that can operate at these high frequencies while consuming little power has proved challenging. One promising approach for fabricating these devices entails the use of carbon nanotubes (CNTs), extremely thin and cylindrical structures with advantageous electrical and thermal properties.

Researchers at Peking University and Stanford University recently developed new flexible and low-power CNT-based transistors that operate at frequencies above 100 GHz. These transistors, presented in a paper published in Nature Electronics, could potentially help to speed up communications between future smartphones, sensors, wearable devices, and other flexible devices.

Single-step 8-9x expansion reveals nanoscale centrioles without electron microscopy

In a study published in ACS Nano, researchers from National Taiwan University report a new expansion microscopy strategy termed high-fold homogeneous expansion microscopy (hiHomoExM), capable of achieving approximately 8–9× isotropic expansion in a single expansion step while preserving delicate ultrastructural organization.

Expansion microscopy works by embedding biological samples within a swellable polymer hydrogel. Following chemical processing, the hydrogel expands uniformly in water, physically separating biomolecules and effectively increasing the spatial resolution achievable by conventional light microscopes.

“To achieve nanoscale imaging faithfully, both high expansion and homogeneous specimen preservation are essential,” explains the research team. “Nonuniform expansion can distort ultrastructural information and limit biological interpretation.”

Teaching thermodynamic laws to AI unlocks a polymer modeling challenge

For more than half a century, materials scientists have struggled with how to simulate the complexity of polymer materials. An individual chain can comprise tens of thousands of atoms, a melt or composite contains billions, and the properties engineers actually care about, such as how an adhesive grips a surface, how a self-assembling block copolymer locks into a nanostructure, or how a biopolymer film stretches without tearing, emerge only over length and time scales that forcible atomistic simulation cannot reach.

The standard workaround is coarse-graining: replacing groups of atoms with simpler mesoscopic particles so the model is fast enough to run. The catch is that this compression almost always sacrifices physics. Conventional coarse-grained polymer models can usually reproduce equilibrium structure or large-scale dynamics, but rarely both, and they routinely fail to capture the entropic and viscous forces that govern how polymers actually flow, relax, and dissipate energy. Those are the forces that dictate mechanical performance, and they are the forces that traditional machine-learning approaches, despite their flexibility, also tend to break.

A research paper recently published in Proceedings of the National Academy of Sciences introduces a new machine-learning framework that lets coarse-grained models achieve both at once. A team from Carnegie Mellon University and the University of Pennsylvania has built an AI architecture that learns coarse-grained dynamics directly from data, whether simulated or experimental, while being mathematically incapable of violating the laws of thermodynamics.

New three‑dimensional magnetic structure discovered with laser light

Flashes of femtosecond laser light, lasting just a few trillionths of a second, have made it possible to observe new magnetic structures for the first time. By using light as a remote control, researchers were able to switch magnetism into previously unseen three-dimensional states at the nanoscale.

Magnetism is often imagined as something simple, pointing in one direction or another. At very small scales, however, magnetism can behave in far more complex ways. Magnetism originates from a quantum property of electrons known as spin, which can be thought of as a tiny internal compass carried by each electron. When many spins interact inside a solid material, they can organize into stable patterns.

Gold-coated optical fiber rapidly gathers microscopic targets for faster, more sensitive detection

Osaka Metropolitan University researchers have developed a light-driven technique that quickly amasses thousands of bacteria into a single spot, boosting detection speed and sensitivity. Their approach paves the way for earlier diagnosis of disease. The study is published in Communications Physics.

Many harmful bacteria, such as E. coli O157, can trigger severe ailments even at very low concentrations. Rapid detection of trace quantities of bacteria is essential to facilitate early diagnosis and prevent disease. The technique could also identify nanoparticles and other micro-and nanoscale entities that are also affecting the immune system and making the disease worse.

“Many conventional techniques are time consuming, require complex instrumentation, or are limited to collecting targets only near a surface or within a narrow focal region,” said Takuya Iida, professor at the Graduate School of Science and Research Institute for Light-induced Acceleration System (RILACS) at Osaka Metropolitan University and lead author of the study.

The quantum key to seeing through chaos

Researchers from the Institut des NanoSciences de Paris, the Kastler Brossel Laboratory and the University of Glasgow have developed an innovative method that renders a scattering medium transparent solely for information carried by entangled photon pairs, while the same medium remains completely opaque to classical light.

Their works are published in the journals Optica (optimization) and Nature Physics (selective image transmission).

Faithfully transmitting spatial information, such as the image of an object, is a major challenge in modern optics. However, this task becomes complex as soon as light travels through disordered media, such as biological tissues, atmospheric turbulence, or multimode optical fibers. In these environments, scattering scrambles the information, making the final image completely unreadable.

Researchers measure giant light-conversion effect in chiral carbon nanotubes

A sheet of twisted carbon nanotubes has revealed a hidden talent scientists suspected for decades but had never managed to measure.

Researchers at Rice University have created large, highly ordered films of chiral carbon nanotubes (CNTs), hollow cylinders of carbon atoms with either a left-or a right-handed twist. Measurements showed the crystalline films can convert the color of light at a rate two to three orders of magnitude greater than conventional materials.

The findings, reported in a study published in ACS Nano, confirm a long-standing theoretical prediction and point toward a future in which ultrathin carbon nanotube films could help power faster optical communications, flexible photonic chips and light-based computing systems that today exist mostly as prototypes.

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