Phys.org October 16, 2024 Thin-film lithium niobate is a promising platform for on-chip photon-pair generation through spontaneous parametric down-conversion (SPDC). However, device implementation faces practical challenges. Periodically poled lithium niobate (PPLN) suffers from poor fabrication reliability and device repeatability, while conventional modal phase matching (MPM) methods yield limited efficiencies. Researchers in Singapore introduced a layer-poled lithium niobate (LPLN) nanophotonic waveguide that significantly enhanced nonlinear interactions for MPM, and achieved normalized second-harmonic generation (SHG) conversion efficiency. Through a cascaded SHG and SPDC process, they demonstrated photon-pair generation with a normalized brightness in a 3.3 mm long LPLN waveguide. According to the […]
Novel visible light communication encryption technology uses chiral nanoparticles
Phys.org October 10,2024 Although recent advancements have been made in active emission or passive conversion of polarized light through solution-processed nanomaterials or metasurfaces, the design paths usually encounter limitations. To address these challenges researchers in the Republic of Korea integrated the spatiotemporal modulation of the LED device, the precise control and efficient polarization emission, and the programmable patterning/positioning using 3D printing. They showed high degree of polarization for both linearly and circularly polarized emission from ultrathin inorganic nanowires and quantum nanorods due to the shear-force-induced alignment effect during the protruding of printing filaments. Real-time polarization modulation was obtained through the […]
Powerful and compact optical frequency combs provide unique opportunities
Phys.org October 11, 2024 Enhanced nonlinear processes in microresonators have emerged as a mainstream comb-generating mechanism with compelling advantages in size, weight, and power consumption. The established understanding of gain and loss in nonlinear microresonators, along with recently developed ultralow-loss nonlinear photonic circuitry, has boosted the optical energy conversion efficiency of microresonator frequency comb (microcomb) devices from below a few percent to above 50%. In this review an international team of researchers (USA – Caltech, Harvard University, Sweden) summarized the latest advances in novel photonic devices and pumping strategies that contributed to these milestones of microcomb efficiency. The resulting benefits […]
Scientists apply ancient construction methods to help fabricate modern microparticles
Phys.org October 15, 2024 An international team of researchers (Singapore, China) has developed a “one-pot microfluidic fabrication” system incorporating two device fabrication strategies, “groove & tongue” and sliding assembling, achieving an array of microparticles with diverse, complex shapes and refined precision, outperforming traditional methods in production rate and quality. Optimally designed sintering profiles based on derivative thermogravimetry enhanced microparticles’ shape retention and structural strength. Compression and scratch tests validated the quality of microparticles. According to the researchers their work advances microscale manufacturing, offering a scalable solution to meet the demanding specifications of miniaturized technology components… read more. Open Access TECHNICAL […]
Scientists use light to visualize magnetic domains in quantum materials
Phys.org October 11, 2024 Researchers in Japan visualized antiferromagnetic domains in a representative quasi-one-dimensional antiferromagnet using nonreciprocal directional dichroism, which differentiated the optical absorption of a pair of antiferromagnetic domains. Opposite antiferromagnetic domains, each about submillimeter in size, were found to coexist in a single-crystal specimen, and the domain walls ran predominantly along the spin chains. They showed that the domain walls could be moved by an applied electric field through a magnetoelectric coupling, and the direction of the domain walls was maintained during the motion. They explained the domain wall anisotropy by the quasi-one-dimensional nature of the exchange interactions. […]
Solar-powered desalination system requires no extra batteries
MIT News October 8, 2024 In the developing world, where there are unreliable energy sources of water, they rely increasingly on saline groundwater. Traditional renewable desalination technologies require sizable energy storage for sufficient water production, leading to increased cost, maintenance and complexity. An international team of researchers (USA – MIT, UK, Germany) demonstrated a simple control strategy using photovoltaic electrodialysis (PV-ED) to enable direct-drive optimally controlled desalination at high production rates. This control scheme was implemented on a fully autonomous, community-scale PV-ED prototype system and operated for 6 months in New Mexico on real brackish groundwater. The prototype fully harnessed 94% […]
Top 10 Science and Technology Inventions for the Week of October 11, 2024
01. Study warns of ‘irreversible’ climate impacts from overshooting 1.5C 02. Bioengineered microorganisms offer new tool for plastic waste breakdown 03. Fused molecules could serve as building blocks for safer lithium-ion batteries 04. Modeling system could enable future generations of self-sensing materials 05. Nanoscale method boosts materials for advanced memory storage 06. New materials and techniques show promise for microelectronics and quantum technologies 07. Restoring quantum dot solar cells as if ‘flattening crumpled paper’ 08. Self-propelled shape-changing robots mimic aquatic insects for untethered swimming 09. Theoretical physicist uncovers how twisting layers of a material can generate a mysterious electron-path-deflecting effect […]
Bioengineered microorganisms offer new tool for plastic waste breakdown
Phys.org October 7, 2024 Mussels exploit the exceptional adhesive properties of 3,4-Dihydroxy-L-phenylalanine (DOPA) to adhere to a wide range of surfaces. Through the optimization of the DOPA incorporation system researchers at Rice University demonstrated significantly improved binding abilities to various organic and metallic materials. DOPA incorporation system was also applied to engineer adhesive bacteria which increased their binding capability to diverse materials including 400 folds of improvement to polyethylene terephthalate (PET). Enhancement in PET binding allowed a unique approach for PET degradation and Genetic Code Expansion in cell engineering… read more. TECHNICAL ARTICLE
Bubble findings could unlock better electrode and electrolyzer designs
MIT News October 8, 2024 The adverse effects of electrochemical bubbles on the performance of gas-evolving electrodes are well known. However, studies on the degree of adhered bubble-caused inactivation, and how inactivation changes during bubble evolution are limited. A team of researchers in the US (MIT, University of Chicago, Argonne National Laboratory) studied electrode inactivation caused by oxygen evolution while using surface engineering to control bubble formation. They found that the inactivation of the entire projected area was poor approximation which led to non-physical results. They analyzed large quantities of experimental data, to show that bubble impacts were small for […]
Chemists use light to replace an oxygen atom with a nitrogen atom in a molecule
Phys.org October 7, 2024 The identity of a heteroatom within an aromatic ring influences the chemical properties of that heterocyclic compound. Chemists have recently introduced a flurry of editing methods to excise individual atoms from molecular frameworks and, in some cases, replace them with alternate functionality. However, systematically evaluating the effect of a single atom poses synthetic challenges, primarily because of thermodynamic mismatches in atomic exchange processes. Researchers in the Republic of Korea developed a photocatalytic strategy that swaps an oxygen atom of furan with a nitrogen group, directly converting the furan into a pyrrole analog in a single intermolecular […]