Phys.org February 15, 2024 A team of researchers in the US (US Naval Research Laboratory, Kansas State University) demonstrated how hexagonal boron nitride (hBN) slabs tuned to the correct thickness act as optical waveguides, enabling direct optical coupling of light emission from encapsulated layers into waveguide modes. They integrated molybdenum selenide (MoSe2) and tungsten selenide (WSe2) within hBN-based waveguides and demonstrated direct coupling of photoluminescence emitted by in-plane and out-of-plane transition dipoles (bright and dark excitons) to slab waveguide modes. They demonstrated that dry etched hBN edges are an effective out-coupler of waveguided light without the need for oil-immersion optics. […]
Researchers develop a computer from an array of VCSELs with optical feedback
Phys.org February 23, 2024 Vertical cavity surface-emitting (VCSEL) arrays offer an attractive platform to develop a photonic Ising computer due to their scalability and compact physical size. Researchers in Singapore computationally investigated the performance of this approach by extending the spin-flip model to describe a system of mutually injection locked VCSELs for 2-, 3-, and 4-bit Ising problems. Numerical simulations demonstrated that the modeled system solved the given Ising problems significantly better than chance, with critical parameters in the model identified as crucial for achieving an unbiased Ising solver. According to the researchers the quantum well gain anisotropy parameter as […]
Researchers develop world-leading microwave photonics chip for high-speed signal processing
Phys.org February 28, 2024 An ideal integrated microwave photonics (MWP) processing platform should have both an efficient and high-speed electro-optic modulation block to faithfully perform microwave–optic conversion at low power and a low-loss functional photonic network to implement various signal-processing tasks, and large-scale, low-cost manufacturability. An international team of researchers (Hong Kong, UK, China) demonstrated such an engine based on a 4-inch wafer-scale thin-film lithium niobate platform. It could perform multipurpose tasks with processing bandwidths of up to 67 GHz at CMOS-compatible voltages. They achieved ultrafast analogue computation. They demonstrated these functions to show three proof-of-concept applications: solving ordinary differential equations, […]
Temperature, humidity may drive future transmission of parasitic worm infections
Phys.org February 26, 2024 Free-living stages of soil-transmitted helminths are highly susceptible to climatic drivers; however, how multiple climatic variables affect helminth species, and the long-term consequences of these interactions, is poorly understood. An international team of researchers (USA – Pennsylvania State University, Italy) used experiments on nine trichostrongylid species of herbivores to develop a temperature- and humidity-dependent model of infection hazard. Intestinal and stomach helminths exhibited contrasting climatic responses, with the former group strongly affected by temperature while the latter primarily impacted by humidity. According to the specific climatic responses of the two groups, climate change is expected to […]
Top 10 Science and Technology Inventions for the Week of February 23, 2024
01. Altermagnetism: A new type of magnetism, with broad implications for technology and research 02. Quantum dark states lead to an advantage in noise reduction 03. Deciphering quantum enigmas: The role of nonlocal boxes in defining the boundaries of physical feasibility 04. Detecting atmospheric rivers with satellite observations 05. Researchers achieve breakthrough in silicon-compatible magnetic whirls 06. Researchers develop world’s most efficient quantum dot solar cell 07. A new design for quantum computers 08. A new record for atom-based quantum computers: 1,000 atomic qubits and rising 09. Physicists develop new solar cell design for better efficiency 10. 14 parameters in […]
14 parameters in one go: New instrument for optoelectronics
Phys.org February 21, 2024 An international team of researchers (Germany, UK, US – NERL, Switzerland, Ukraine) developed the constant light induced magneto transport method which resolves electron and hole mobility, lifetime, diffusion coefficient and length, and quasi-Fermi level splitting and demonstrated their implication of the constant light induced magneto transport for silicon and metal halide perovskite films. They resolved the transport properties of electrons and holes predicting the material’s effectiveness for solar cell application without making the full device. The accessibility of fourteen material parameters paved the way for in-depth exploration of causal mechanisms limiting the efficiency and functionality of […]
Altermagnetism: A new type of magnetism, with broad implications for technology and research
Phys.org February 14, 2024 Altermagnets have a special combination of the arrangement of spins and crystal symmetries. The spins alternate, as in antiferromagnets, resulting in no net magnetization. Rather than simply canceling out, the symmetries give an electronic band structure with strong spin polarization that flips in direction as you pass through the material’s energy bands resulting in highly useful properties more resemblant to ferromagnets, as well as some completely new properties. An international team of researchers (Switzerland, Germany, Czech Republic, Austria, Colombia, UK) has proved the existence of altermagnetism. They provided the confirmation using photoemission spectroscopy and ab initio […]
Coordination polymer crystals show promise as new generation of light sources for industry, medicine
Phys.org February 20, 2024 Luminescent lanthanide coordination polymer crystals (LCPCs) provide a high level of structural tunability, including size- and morphology-dependent properties; therefore, they are promising materials for next-generation phosphors in a wide range of applications such as light emitting diodes. By controlling the morphology of thermostable europium coordination polymer crystals researchers in Japan developed a novel red phosphor with narrow linewidth emission and characterized them through analysis. Size tunable crystalline polymer spheres had high internal quantum efficiency and high thermostability, and exhibited dispersibility in PMMA Poly(methyl methacrylate) media… read more. Open Access TECHNICAL ARTICLE
Deciphering quantum enigmas: The role of nonlocal boxes in defining the boundaries of physical feasibility
Phys.org February 14, 2024 Nonsignaling boxes (NS) are theoretical resources defined by the principle of no-faster-than-light communication. They generalize quantum correlations and some of them are known to collapse communication complexity (CC). However, this collapse is strongly believed to be unachievable in nature. An international team of researchers (France, Canada) provided intuition on which theories are unrealistic. They found a better sufficient condition for a nonlocal box to collapse CC, thus extended the known collapsing region. In some slices of NS, they showed that this condition coincides with an area outside of an ellipse… read more. TECHNICAL ARTICLE Full […]
Detecting atmospheric rivers with satellite observations
Phys.org February 19, 2024 Atmospheric rivers (ARs) are filaments of enhanced horizontal moisture transport in the atmosphere. They play a prominent role in the meridional moisture transport and regional weather extremes. But the representations of ARs and their associated precipitation on a global scale remains largely unknown. A team of researchers in the US (UCLA, NCAR, Caltech) developed an AR detection algorithm specifically for satellite observations using moisture and the geostrophic winds derived from 3D geopotential height field from the combined retrievals of the Atmospheric Infrared Sounder and the Advanced Microwave Sounding Unit on NASA Aqua satellite. The algorithm enabled […]