Hot spots: this photo composition has a locust (centre) showing the location of the nanoparticles (left), which are illuminated by near-infrared light (illustrated in red). (Courtesy: Singamaneni Lab/Washington University) Using specially engineered nanoparticles, a team of US researchers has artificially enhanced the sense of smell in locusts. Led by Srikanth Singamaneni and Barani Raman at Washington University in St Louis, the researchers’ approach could lead to a new type of biological chemical sensors. Many different animals have evolved a sense of smell that vastly outperforms our own. E ..read more

A distinctive iridescent patina on an ancient Roman glass fragment stems from a photonic crystal structure that formed naturally within the material over time, say researchers in Italy and the US. The unusual crystal contains alternating layers of high- and low-density silica layers that resemble reflectors known as Bragg stacks, and their presence makes the fragment’s surface shine like a gold mirror. As well as revealing the nanoscale characteristics of ancient glass, the discovery is an example of naturally-nanofabricated complex photonic architecture – something that could inspire new stra ..read more

If you stir a colloidal solution containing nanoparticles, you might expect the particles to disperse evenly through the liquid. But that’s not what happens. Instead, the particles end up concentrated in a specific region, and may even clump together. This unexpected result is an example of Einstein’s tea leaf paradox, and the researchers at Tongji University in China who discovered it – quite by accident – say it could be used to collect particles or molecules for detection in a dilute solution. Importantly, it could also be used to make aerogels for technological applications. We usually sti ..read more

It has been a very exciting week in the world of physics. The winners of the 2023 Nobel Prize for Physics were announced on Tuesday and on Wednesday we learned that this year’s chemistry prize has a very strong connection to physics. And to top it all off, the names of the chemistry winners were leaked several hours before the announcement was made. So we definitely have lots to talk about in this episode of the Physics World Weekly podcast, which features Physics World’s Margaret Harris, Matin Durrani and Hamish Johnston. Physics World‘s Nobel prize coverage is supported by Oxford Instrumen ..read more

The Nobel Prize for Chemistry has been won by Moungi Bawendi, Louis Brus and Alexei Ekimov for “the discovery and synthesis of quantum dots”. Quantum dots are extremely small particles just a few atoms in size and their properties allow them to emit light at specific wavelengths. Since the 1930s physicists had known that, in theory, quantum effects could arise in nanoparticles that would give them unusual characteristics, but for decades it was difficult to create such materials in the laboratory. That changed in the early 1980s, when Ekimov, who had a background in semiconductors, succeeded i ..read more

How it works: composite image showing illustrations of the de-icing process and electron microscope images of the nanowire surface. (Courtesy: Siyan Yang, Qixun Li, Bingang Du, Yushan Ying, Yijun Zeng, Yuankai Jin, Xuezhi Qin, Shouwei Gao, Steven Wang, Zuankai Wang, Rongfu Wen and Xuehu Ma) A passive coating that is almost 100% effective at removing ice and frost from surfaces has been unveiled by researchers in China. The team’s design features an array of copper nanowires that combine excellent photothermal, heat-conducting, and superhydrophobic properties to achieve a very high defrosting e ..read more

Physicists in China have developed a technique for simultaneously measuring the mass and temperature of a single nanoparticle. The technique, which involves levitating the nanoparticle in an optical trap, applying a sinusoidal electrostatic force to it and analysing its subsequent trajectory, will help scientists determine how the properties of nanoparticles change in response to changes in temperature. Nanoparticles are found in a wide range of products, including cosmetics, paints, food products and pharmaceuticals. To optimize their performance in these diverse applications, it is essential ..read more

Assemblies of quantum dots tend to be highly disordered, but when the facets of these tiny semiconducting structures are lined up like soldiers on parade, something strange happens: the dots become very good at conducting electricity. This is the finding of researchers at the RIKEN Center for Emergent Matter Science in Japan, who say that these ordered, quasi-two-dimensional “superlattices” of quantum dots could make it possible to develop faster and more efficient electronics. Quantum dots are semiconductor structures that confine electrons in all three spatial dimensions. This confinement me ..read more

Physicists in the US have discovered a laser-based “switch” that turns a sample of ions completely transparent at certain frequencies. Working at the California Institute of Technology (Caltech), the team found that when they coupled ytterbium ions (Yb3+) to a nanophotonic resonator and strongly excited them with laser light, the ions abruptly stopped reflecting light at frequencies associated with their vibrations. This effect, which the team dub “collectively induced transparency”, could have applications in quantum optical devices. “We discovered the phenomenon while trying to develop techn ..read more

Researchers in Israel have uncovered the unique optical nanostructure that gives an ocean-going scavenger its brilliant white colouring. Using a range of imaging techniques, a team led by Benjamin Palmer at Ben-Gurion University of the Negev, Israel, showed that spherical particles in Pacific cleaner shrimp scatter incoming light in all directions, while avoiding any overlap in the scattering patterns they produce. The discovery could lead to new bio-inspired white pigments. Many organisms have evolved the ability to manipulate light in unique and fascinating ways. Mimicking these mechanisms h ..read more