EurekAlert April 6, 2021 An international team of researchers (South Korea, Hong Kong) designed an artificial structure that can control not only the domain of underwater sound but also vibration. The research team has presented an underwater stealth metasurface independent from SONAR by controlling the acoustic resonance to absorb the wave. They also confirmed that the wave propagation through a curved plate, such as vibrations, can be drastically altered. Their methodology can achieve the cloaking effect with singularity of infinite refractive index. They designed a thin metasurface to absorb sound waves in broadband (14 kHz to 17 kHz). The metasurface […]
Tag Archives: Sensors
Toward perdurable flexible electronics
Nanowerk March 23, 20212 In wearable electronics, to acquire stability and simultaneously preserve stretchability, sensitivity, and scalability is of high significance yet challenging for practical device applications. Researchers in Japan developed a kirigami-structured graphene–polymer hybrid nanocomposite for strain sensors by a laser direct writing technique on a polyimide sheet. To protect the device, ecoflex polymer was applied as the passivation layer. Depending on the applications, ecoflex grid-wrapped and film-encapsulated have high stretchability and sensitivity. In demonstrations the sensor platform suffered almost no performance degradation even after >60 000 stretching cycle tests due to less strain within the sensor. As proof-of-concept for […]
Army Trains AI to Identify Faces in the Dark
IEEE Spectrum March 9, 2021 To develop a nighttime and low-light face recognition capability for the unconstrained or difficult lighting settings a team of researchers in the US (West Virginia University, Army Research Laboratory, Johns Hopkins University, University of Nebraska, industry) unveiled a dataset called Research Laboratory Visible-Thermal Face Dataset (ARLVTF) with over 500,000 images from 395 subjects. The data was captured using a LWIR camera mounted alongside a stereo setup of three visible spectrum cameras. Variability in expressions, pose, and eyewear were systematically recorded. The dataset has been curated with extensive annotations, metadata, and standardized protocols for evaluation. The […]
Capturing Free-Space Optical Light for High-Speed WiFi
Duke University February 9, 2021 Visible and infrared light can carry more data than radio waves, but has always been confined to a hard-wired, fiber-optic cable. A team of researchers in the US (Duke University, industry) has demonstrated a low-loss plasmonic metasurface that can collect fast-modulated light with a 3 dB bandwidth exceeding 14 GHz and a 120º acceptance angle and convert it to a directional source with an overall efficiency of ∼30%. This exhibits a 910-fold increase in the overall fluorescence and a 133-fold emission rate enhancement. The metasurface was created over macroscopic areas with scalable techniques and the […]
Researchers design next-generation photodetector
EurekAlert February 2, 2021 State-of-the-art LWIR detection technology still suffers from shortcomings such as low photocurrent gain and excess spectral noise. Researchers at Northwestern University used a new approach to design the photodetector using a type-II superlattice, a material system known for its outstanding growth uniformity and exceptional band structure engineering and applied the new material to a heterojunction phototransistor device structure. During testing each part of the photodetector was tuned to use the phototransistor to achieve high optical gain, low noise, and high detectivity. The material’s flexibility allowed for meticulous quantum mechanics-based band structure engineering for the heterostructure design, […]
Ultrathin spray-applied MXene antennas are ready for 5G
Science Daily November 30, 2020 Only conventional metals meet the requirements for emerging RF devices so far. A team of researchers in the US (Drexel University, Villanova University, industry) has developed Ti3C2Tx MXene microstrip transmission lines with low‐energy attenuation and patch antennas with high‐power radiation at frequencies from 5.6 to 16.4 GHz. The antenna was manufactured by spray‐coating from aqueous solution. They demonstrated that an MXene patch antenna array with integrated feeding circuits on a conformal surface has comparable performance with that of a copper antenna array at 28 GHz, which is a target frequency in practical 5G applications. The […]
No losses: Scientists stuff graphene with light
EurekAlert November 16, 2020 Researchers in Russia developed a technique to achieve 90% energy conversion from the pump laser field to the surface plasmon polaritons (SPPs) on the base of the hybrid optoplasmonic multi‐level scheme of near‐resonant interaction with semiconductor quantum dots (QDs) placed in the proximity of a graphene surface. Using numerical simulations and semiclassical approach for the light–matter interaction they found that maximum efficiency of SPP generation is achieved in strong coupling conditions for a stationary regime of SPP‐QD interaction. The technique can be used for converting energy in solar cells, and nano and bio-object detection…read more. TECHNICAL […]
The next biometric identifier? 3D images of your finger veins
Technology.org November 10, 2020 Biometric methods based on finger veins, as compared to face and fingerprints, obviate privacy concerns and degradation due to wear, age, and obscuration. However, they are 2D and are fundamentally limited by conventional imaging and tissue-light scattering. A team of researchers in the US (SUNY Buffalo, industry) has developed a method of 3D finger vein biometric authentication based on photoacoustic tomography. Using a compact photoacoustic tomography setup and a novel recognition algorithm, they demonstrated the advantages of the 3D biometrics method. Tests of the method on people showed that it can correctly accept or reject an […]
Researchers develop a high-power, portable terahertz laser
MIT News November 2, 2020 Until now, generation of terahertz radiation powerful enough to perform real-time imaging and fast spectral measurements required temperatures far below 200 kelvins (-100 degrees Fahrenheit) or lower. An international team of researchers (USA – MIT, Canada) has developed THz QCLs (at ~4 THz) with a maximum operating temperature of 250 K. The high operating temperature enables portable THz systems to perform real-time imaging with a room-temperature THz camera, as well as fast spectral measurements with a room-temperature detector…read more. TECHNICAL ARTICLE
Scientists develop ‘mini-brains’ to help robots recognize pain and to self-repair
Science Daily October 15, 2020 Sensory information processing in robot skins currently rely on a centralized approach where signal transduction is separated from centralized computation and decision-making, requiring the transfer of large amounts of data from periphery to central processors. An international team of researchers (Singapore, Italy) took a decentralized approach where intelligence is embedded in the sensing nodes, using a unique neuromorphic methodology to extract relevant information in robotic skins. They proposed a system to address pain perception and the association of nociception with tactile perception to trigger the escape reflex in a sensitized robotic arm. The system comprises […]