American Physical Society Synopsys May 29, 2018 Magnetic cloaks typically use superconducting materials, which must be cooled to cryogenic temperatures. An international team of researchers (China, Sweden) has built a room-temperature cloak that does not employ superconductors. Such a cloak could be useful in shielding sensitive devices from external magnetic fields. Their cloak consists of a hollow cylinder made of several foils of a high-magnetic-permeability material with copper wires running along the cylinder’s length. When currents pass through the wires shields the interior of the cylinder from external magnetic fields. Experiments demonstrated that the device works at room temperature for […]
Category Archives: Sensors
Improving mid-infrared imaging and sensing
Eurekalert April 26, 2018 Making use of a mid-infrared femtosecond laser coupled with a parametric amplifier, an international team of researchers (MIT, UMass Lowell, China) developed a system that turns regions of molecules in the open air into glowing filaments of plasma. They proved that it did indeed work as expected. It opens the potential for detecting a very wide range of compounds in the air, from a distance. The system can detect various biohazards and pollutants by detecting the exact color of the filament and analyzing the absorption spectrum… read more. Open Access TECHNICAL ARTICLE
For nuclear weapons reduction, a way to verify without revealing
Science Daily April 19, 2018 Researchers at MIT present a concept that leverages isotope-specific nuclear resonance phenomena to authenticate a warhead’s fissile components by comparing them to a previously authenticated template. All information is encrypted in the physical domain in a manner that amounts to a physical zero-knowledge proof system. Using Monte Carlo simulations, the system is shown to reveal no isotopic or geometric information about the weapon, while readily detecting hoaxing attempts. The method is a physical analog of data encryption. The team has verified the neutron concept through extensive simulations and now hopes to prove that it works […]
Invisible magnetic sensors measure magnetic fields without disturbing them
Phys.org April 25, 2018 Researchers in Spain present a general strategy on how to make a sensor magnetically invisible while keeping its ability to sense. The sensor is rendered undetectable by surrounding it with a spherical shell having a tailored magnetic permeability. The method can be applied to arbitrary shape magnetic sensors in arbitrary magnetic fields. The invisibility can be made exact when the sensor is spherical, and the probed field is uniform. They are exploring cloaking properties for AC fields or incorporating the intriguing concept of negative static permeability for creating novel shapes of magnetic fields… read more. Open […]
Portable device to sniff out trapped humans
Science Daily April 18, 2018 An international team of researchers (Switzerland, Austria, Cyprus) presents a pilot study with compact and orthogonal sensor arrays to detect the breath- and skin-emitted metabolic tracers acetone, ammonia, isoprene, CO2, and relative humidity, all together serving as sign of life. It consists of three nanostructured metal-oxide sensors (Si-doped WO3, Si-doped MoO3, and Ti-doped ZnO), each specifically tailored at the nanoscale for highly sensitive and selective tracer detection along with commercial CO2 and humidity sensors. When tested on humans enclosed in plethysmography chambers to simulate entrapment, this sensor array rapidly detected sub-ppm acetone, ammonia, and isoprene […]
Virtual contact lenses for radar satellites
Science Daily April 16, 2018 Water level from sea ice-covered oceans is particularly challenging to retrieve with satellite radar altimeters due to the different shapes assumed by the returned signal compared with the standard open ocean waveforms. An international team of researchers (Germany, Denmark, UK, Italy) has developed a fitting (also called retracking) strategy (ALES+) based on a subwaveform retracker that is able to adapt the fitting of the signal depending on the sea state and on the slope of its trailing edge. The algorithm modifies the existing Adaptive Leading Edge Subwaveform retracker originally designed for coastal waters and is […]
New laser technique may help detect chemical warfare in atmosphere
Phys.org March 26, 2018 A team of researchers in the US (University of Central Florida, industry partner) present a new platform for mid-infrared dual-comb Fourier-transform spectroscopy based on a pair of ultra-broadband subharmonic optical parametric oscillators pumped by two phase-locked thulium-fibre combs. The system provides fast, moving-parts-free, simultaneous acquisition of 350,000 spectral data points and parallel detection of 22 trace molecular species in a gas mixture. It can detect at concentrations of one part per billion. The research could open the door for developing non-invasive technology, including sensors for airborne agents and traces of life in space… read more. TECHNICAL […]
Compact fiber optic sensor offers sensitive analysis in narrow spaces
Science Daily March 15, 2018 Researchers in China have developed a refractive index sensor based on an S-tapered fiber probe with a silver mirror on its end facet. It can sense concentration, pH and other chemical parameters. They have demonstrated that the device is nine times more sensitive than other tapered fiber refractive index sensors, requires very little sample for analysis and measurements are not affected by temperature changes. The sensor’s small size, about 1mm, means that it could potentially be used inside blood vessels. With additional development, the sensor might be used to detect specific chemicals, DNA molecules or […]
‘Frequency combs’ ID chemicals within the mid-infrared spectral region
Eurekalert March 15, 2018 Chemical compounds all carry distinctive absorption “fingerprints” within the mid-infrared spectral region of 2 to 12 microns. A team of researchers in the US (NIST Colorado, University of Colorado, NIST Maryland) leveraged robust fabrication and geometrical dispersion engineering of nanophotonic waveguides for multi-band, coherent frequency combs spanning 70 THz in the midinfrared (2.5 µm–6.2 µm). Precise waveguide fabrication provides significant spectral broadening with engineered spectra targeted at specific mid-infrared bands. They have numerous applications — from transferring time standards and improving GPS signals to precision spectroscopy. These sensors can significantly increase the detection sensitivity of tools […]
Inspired by insects: New anti-collision technology could help create safer driverless cars
Eurekalert March 15, 2018 An international team of researchers (UK, Germany, China, Japan, Malaysia, South America) is working on a EU sponsored project called ULTRACEPT (Ultra-layered perception) with brain-inspired information processing for vehicle collision avoidance. It was inspired by the rapid reactions of insects, incorporating near-range collision detection technology, long-range hazard perception, and thermal-based collision detection tools. This will ensure that it works day and night and can quickly adapt to unexpected hazards and different conditions – for example sudden weather changes or driving in and out of tunnels… read more.