Phys.org July 22, 2021 Researchers at Los Alamos National Laboratory propose that modulated quantum metasurfaces can control all properties of photonic qubits, a breakthrough that could impact the fields of quantum information, communications, sensing and imaging, as well as energy and momentum harvesting. They developed a metasurface that looked like an array of rotated crosses, then proposed to shoot a single photon through the metasurface, where the photon splits into a superposition of many colors, paths, and spinning states generating quantum entanglement meaning the single photon can inherit different properties at once. According to the researchers by manipulating these properties, […]
Tag Archives: Imaging technology
Nanostructures enable record high-harmonic generation
Phys.org July 21, 2021 Resonantly enhanced High harmonic generation (HHG) from hot spots in nanostructures is an attractive route to overcoming the well-known limitations of gases and bulk solids. An international team of researchers (USA – Cornell University, Ohio State University, Singapore) demonstrated an ultra-thin resonant gallium phosphide platform for highly efficient HHG driven by intense mid-infrared laser pulses. The gallium-phosphide material permits harmonics of all orders without reabsorbing them, and the specialized structure can interact with the laser pulse’s entire light spectrum. The enhanced conversion efficiency facilitates single-shot measurements that avoid material damage and pave the way to study […]
New method predicts ‘stealth’ solar storms before they wreak geomagnetic havoc on Earth
Phys.org July 20, 2021 Unlike coronal mass ejections which typically show up clearly on the Sun as dimming or brightening, the ‘stealth CMEs’ often originate at higher altitudes in the Sun’s corona, in regions with weaker magnetic fields and they are usually only visible on coronagraphs designed to reveal the corona. An international team of researchers (USA – UC Berkeley, industry, University of Maryland, NASA, Belgium, Romania, UK, India, Russia) has shown that many stealth CMEs can be detected in time if current analysis methods for remote sensing are adapted. They compared remote sensing images of the Sun with the […]
Scientists achieve single-photon imaging over 200 kilometers
Phys.org April 5, 2021 The operating range of practical single photon lidar systems is limited to about tens of kilometers over the Earth’s atmosphere, mainly due to the weak echo signal mixed with high background noise. By using high-efficiency optical devices for collection and detection, and new noise-suppression technique that is efficient for long-range applications researchers in China have developed a compact coaxial single-photon lidar system capable of realizing 3D imaging at up to 201.5 km. They developed photon-efficient computational algorithms which enabled accurate imaging with as few as 0.44 signal photons per pixel. The research is a significant step […]
Object classification through a single-pixel detector
Phys.org March 29, 2021 To mitigate the shortcomings and inefficiencies of traditional machine vision systems researchers at UCLA leveraged deep learning to design optical networks created by successive diffractive surfaces to perform computation and statistical inference as the input light passes through specially designed and 3D-fabricated layers. The diffractive optical networks are designed to process the incoming light at selected wavelengths with the goal of extracting and encoding the spatial features of an input object onto the spectrum of the diffracted light, which is collected by a single-pixel detector. Different object types or classes of data are assigned to different […]
Tiny terahertz laser is the first to reach three key performance goals at once
Nanowerk December 30, 2020 A photonic wire laser (PWL) is a type of laser built on a semiconductor chip that has nanometer-sized bore and a millimeter length cavity. Coupling multiple adjacent PWLs can synchronize the light beams to emit at the same or multiple wavelengths and combine their power. A team of researchers in the US (MIT, Sandia National Laboratory) proposed and demonstrated a scheme to form a coupled cavity by taking advantage of this unique feature of photonic wire lasers. They used quantum cascade lasers with antenna-coupled third-order distributed feedback grating as the platform. Inspired by the chemistry of […]
Invisible organic light-emitting diodes reach new world record
EurekAlert November 11, 2020 Inspired by a class of molecules previously used for biomedical imaging researchers in Canada developed two new organic compounds with emission peak at a wavelength of 840 nm. The OLED showed a quantum efficiency of 3.8%. The latter corresponds to the percentage of electrons circulating throughout the device, electrons which are then converted into useable light. The efficiency is more than three times higher than that of the best previously reported fluorescent OLEDs in this spectral range and approaches that achievable with the best platinum‐containing phosphorescent emitters. The device has possible applications in biomedicine, facial recognition, […]
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 […]
Image cloaking tool thwarts facial recognition programs
TechXplore August 5, 2020 To help individuals inoculate their images against unauthorized facial recognition models, researchers at the University of Chicago have developed a system called Fawkes. It helps individuals add imperceptible pixel-level changes (they call “cloaks”) to their own photos before releasing them. When used to train facial recognition models, the “cloaked” images produce functional models that consistently cause normal images of the user to be misidentified. In experiments Fawkes provided 95+% protection against user recognition regardless of how trackers train their models. They have shown that Fawkes is robust against a variety of countermeasures that try to detect […]
Nano-thin flexible touchscreens could be printed like newspaper
Nanowerk January 24, 2020 Researchers in Australia used a thin film common in cell phone touchscreens and shrunk it from 3D to 2D, using liquid metal chemistry. They synthesized flexible two-dimensional indium tin oxide (ITO) using a low-temperature liquid metal printing technique. The approach can directly deposit monolayer or bilayer ITO onto desired substrates, with the resulting bilayer samples offering a transparency above 99.3% and a sheet with low resistance. To illustrate the capabilities of the technique, they developed a capacitive touch screen using centimetre-sized monolayer ITO sheets…read more. TECHNICAL ARTICLE