Phys.org February 9, 2023 Avalanche photodiodes (APDs) have internal gain, which means that when compared to PIN-photodiodes they typically have a higher signal-to-noise ratio. Researchers in the UK designed and demonstrated photodiode that exhibits high multiplication factor with very little added noise. The new semiconductor alloy is based on a GaAsSb absorption region that has excellent detection efficiency at infrared wavelengths (up to 1,700 nanometers). The device incorporated an appropriate doping profile to suppress tunneling current from the absorption region, achieving a large avalanche gain, ∼130 at room temperature. It exhibits extremely low excess noise factors of 1.52 and 2.48 […]
Tag Archives: S&T UK
New ice is like a snapshot of liquid water
Science Daily February 2, 2023 The new form of ice is amorphous. Unlike ordinary crystalline ice where the molecules arrange themselves in a regular pattern, in amorphous ice the molecules are in a disorganised form that resembles a liquid. Researchers in the UK created a new form of amorphous ice by grinding crystalline ice into small particles using metal balls in a steel jar. They created a novel amorphous form of ice which had a density similar to that of liquid water and whose state resembled water in solid form. They named the new ice medium-density amorphous ice (MDA). To […]
Tropical storms signaled by atmospheric waves, study finds
Phys.org February 7, 2023 Understanding and prediction of tropical cyclone (TC) activity on the medium range remains challenging. Researchers in the UK found that the pre-existing westward-moving equatorial waves can inform the risk of TC occurrence and intensification, based on a dataset obtained by synchronising objectively identified TCs and equatorial waves in a climate reanalysis. Globally, westward-moving equatorial waves can be precursors to 60–70% of pre-tropical cyclogenesis events, and to >80% of the events with the strongest vorticity, related to the favourable environmental conditions within the pouch of equatorial waves. They also found that when storms are in-phase with westward-moving […]
The optical fiber that keeps data safe even after being twisted or bent
Science Daily January 10, 2023 Topological states enable robust transport within disorder-rich media. However, to exploit topological protection in a length-scalable platform such as optical fiber remains a challenge. Through modeling and experiment a team of researchers in the UK demonstrated that optical fiber hosts topological supermodes across multiple light-guiding cores. They directly measured the photonic winding number invariant characterizing the bulk and observed topological guidance of visible light over meter length scales. The mechanical flexibility of fiber allowed them to reversibly reconfigure the topological state. As the fiber was bent, they found that the edge states first lost their […]
Signal processing algorithms improved turbulence in free-space optic tests
Science Daily December 20, 2022 Researchers in the UK used commercially available photonic lanterns, a commercial transponder, and a spatial light modulator to emulate turbulence. They simultaneously transmitted multiple data signals using different spatially shaped beams of light using a photonic lantern. By detecting light with these shapes using a second lantern, more of the light is collected at the receiver, and the original data can be unscrambled greatly reduce the impact of the atmosphere on the quality of the data received in MIMO digital signal processing. By transmitting multiple beams of different shapes through the same telescopes and detecting […]
Team creates protein-based material that can stop supersonic impacts
Phys.org December 13, 2022 Extreme energy dissipating materials are essential for a range of applications, in the military, law enforcement, aerospace industry to name a few. Researchers in the UK have created and patented a new shock-absorbing material that could revolutionize both the defense and planetary science sectors. They incorporated a recombinant form of the mechanosensitive protein talin into a monomeric unit and crosslinked, resulting in the production of a talin shock absorbing material (TSAM). When subjected to 1.5 km/s supersonic shots, TSAMs were shown not only to absorb the impact, but to capture/preserve the projectile. According to the researchers […]
Underwater tsunamis created by glacier calving cause vigorous ocean mixing
Phys.org November 24, 2022 Researchers in the UK took ocean measurements close to the William Glacier, situated on the Antarctic Peninsula. It has one or two large calving events per year, and the team estimated this one broke off around 78,000 square meters of ice. Before it broke away, the water temperature was cooler at around 50-100 meters in depth, and warmer below this. After the calving temperature was much more even across different depths. Glaciers that end up in the sea cause big waves at the surface and create waves inside the ocean causing the sea to mix. This […]
Ultrathin solar cells promise improved satellite performance
Nanowerk November 8, 2022 Ultra-thin solar cells’ radiation tolerance may allow them to be used in harsh radiation environments, where thicker cells would degrade rapidly. Researchers in the UK irradiated devices with an 80 nm GaAs absorber layer with 3 MeV protons. They mapped the introduction of radiation-induced defects with increasing proton fluence and characterized a decrease in carrier lifetime after irradiation fluence. Despite the substantial reduction in carrier lifetime, short-circuit current did not degrade up to a proton fluence of 1 × 1015 cm−2, beyond which the short-circuit current collapsed. The exposure correlated with the point at which the carrier lifetime became comparable to […]
New Hybrid Virus Discovered as Flu And RSV Fuse Into Single Pathogen
Science Alert October 31, 2022 Interactions between respiratory viruses during infection affect transmission dynamics and clinical outcomes. To identify and characterize virus–virus interactions at the cellular level, researchers in the UK coinfected human lung cells with influenza A virus (IAV) and respiratory syncytial virus (RSV). Super-resolution microscopy, live-cell imaging, scanning electron microscopy and cryo-electron tomography revealed extracellular and membrane-associated filamentous structures consistent with hybrid viral particles (HVPs). They found that HVPs harbor surface glycoproteins and ribonucleoproteins of IAV and RSV. HVPs use the RSV fusion glycoprotein to evade anti-IAV neutralizing antibodies and infect and spread among cells lacking IAV receptors…read […]
Insect Swarms Can Electrify The Air as Much as a Thunderstorm
Science Alert October 25, 2022 The atmosphere hosts multiple sources of electric charge that influence critical processes such as the aggregation of droplets and the removal of dust and aerosols. Whereas these electric fields are known to respond to physical and geological processes, the effect of biotic sources of charge has not hitherto been considered. Researchers in the UK combined theoretical and empirical evidence to demonstrate that honeybee swarms directly contribute to atmospheric electricity, in proportion to the swarm density. They provided a quantitative assessment of this finding, by comparing the electrical contribution of various swarming insect species with common […]