Phys.org March 4, 2024 The coherence time of the quantum system surpasses that of the oscillator probing the system. Correlation spectroscopy overcomes this limitation by probing two quantum systems with the same noisy oscillator for a measurement of their transition frequency difference enabling very precise comparisons of atomic clocks. An international team of researchers (Austria, Israel, USA – Caltech) extended correlation spectroscopy to the case of multiple quantum systems undergoing strong correlated dephasing. They modelled Ramsey correlation spectroscopy with N particles as a multiparameter phase estimation problem and demonstrated that multiparticle correlations could assist in reducing the measurement uncertainties even […]
Category Archives: Sensors
Research team develops a wireless sensor for spotting chemical warfare agents
Phys.org March 5, 2024 Researchers in China developed a 433 MHz passive wireless surface acoustic wave (WSAW) gas sensor for dimethyl methyl phosphonate (DMMP) detection. It includes a YZ lithium niobate (LiNbO3) substrate with metallic interdigital transducers (IDTs) etched on it, and an antenna was placed near the IDT… read more. Open Access TECHNICAL ARTICLE
Researchers turn a small photonic chip into a functional temperature sensor
Phys.org December 15, 2023 An international team of researchers (Belgium, Greece, Czech Republic) showed described in detail the process to obtain a fully packaged miniature photonic temperature sensor starting from bare PIC dies having Bragg grating sensors in a silicon waveguide. The PIC was interfaced from the back side using a 300 μm ball lens ensuring that the top surface remained clear of any interfacing fibers. Based on this they developed a solution for integrating a 1 mm × 1 mm sensor PIC with a single-mode fiber and packaging it in a 1.5 mm inner-diameter metal protective tube. A packaged […]
Researchers test seafloor fiber optic cable as an earthquake early warning system
Science Daily October 17, 2023 An international team of researchers (USA – Caltech, industry, Chile) provided a real‐data test for offshore earthquake early warning (EEW) with distributed acoustic sensing (DAS) by transforming submarine fiber‐optic cable into a dense seismic array. They constrained earthquake locations using the arrival‐time information recorded by the DAS array and earthquake magnitudes were estimated directly from strain rate amplitudes by applying a scaling relation transferred from onshore DAS arrays. According to the researchers their results indicate that using this single 50 km offshore DAS array can offer ∼3 s improvement in the alert time of EEW […]
Novel thermal sensor could help drive down the heat
Science Daily July 24, 2023 Excess heat from electronic or mechanical devices is a sign or cause of inefficient performance. In many cases, embedded sensors to monitor the flow of heat could help engineers alter electronic or mechanical devices behavior or designs to improve their efficiency. Researchers in Japan explored the way a heat flux sensor consisting of certain special magnetic materials and electrodes behaves when there are complex patterns of heat flow. They etched desired patterns into the resultant film, similar to how electronic circuits are made. They designed the circuits in a particular kind of way to boost […]
Proposed metamaterial could have a wide range of applications, from sensing to stealth technology
Phys.org July 17, 2023 Materials scientists are actively hunting for metamaterials that are “perfect absorbers” of electromagnetic radiation with controllable resonance characteristics that lead to their wide usage in applications as varied as solar cells, thermal radiation imaging, sensing technology, and even stealth technology. An international team of researchers (Pakistan, USA – University of Alabama) has developed a triple-band perfect metamaterial absorber in terahertz regime that is made of asymmetric metallic I-shaped resonator and metallic ground layer with dielectric spacer in the middle. The simulated results showed that the absorption device had three resonance modes with corresponding absorption rate close […]
Graphene quantum dots show promise as novel magnetic field sensors
Nanowerk March 6, 2023 Single quantum dots and coupled quantum dots formed with massless Dirac fermions can be viewed as artificial relativistic atoms and molecules, respectively. Such structures offer a unique testbed to study atomic and molecular physics in the ultrarelativistic regime. An international team of researchers (USA – UC Santa Cruz, UK, Japan) used a scanning tunnelling microscope to create and probe single and coupled electrostatically defined graphene quantum dots to unravel the magnetic-field responses of artificial relativistic nanostructures. When electrons in graphene are confined in a quantum dot, they travel in circular loops around the edge of the […]
Electronic nose: Sensing the odor molecules on graphene surface layered with self-assembled peptides
Science Daily January 19, 2023 Researchers in Japan designed and developed three new peptides for graphene biosensors that can detect odor molecules to perform two main functions — acting as a biomolecular scaffold for self-assembly on a graphene surface and functioning as a bio-probe to bind the odor molecules. They showed that the peptides uniformly covered the graphene surface with the thickness of a single molecule. When representative odor molecules were injected into the functionalized graphene field-effect transistors (GFETs), graphene conductivity reduced indicating the binding of the odor molecules. The odor molecules gave rise to distinct signatures confirming that the […]
New nanowire sensors are the next step in the Internet of Things
Phys.og January 6, 2023 Despite intensive research and rapid progress in self-powered gas devices, most reported devices, specifically NO2 sensors for air pollution monitoring, have limited sensitivity, selectivity, and scalability. Researchers in Australia have demonstrated a photovoltaic self-powered NO2 sensor based on axial p–i–n homojunction InP nanowire (NW) arrays, that overcame these limitations. The device was designed by numerical simulation for insights into sensing mechanisms and performance enhancement. Without a power source, the InP NW sensor achieved an 84% sensing response to 1 ppm NO2 and recorded a limit of detection down to the sub-ppb level, with little dependence on […]
Flexible strain sensor enabled by carbon nanofibers can ‘read lips’
Phys.org November 29, 2022 While high sensitivity and wide working range are desired key parameters for a strain sensor, they are usually contrary to each other to be achieved on the same sensor due to the tight structure dependence of both. Researchers in China used an integrated membrane containing both parallel aligned and randomly aligned carbon nanofibers (CNFs) to design a flexible strain sensor with high sensitivity and wide strain detection range. The parallel aligned CNF membrane (p-CNF) exhibited a low strain detection limit and high sensitivity, while the random aligned CNF membrane (r-CNF) exhibits a large strain detection range. […]