Phys.org January 23, 2023 Imaging through scattering medium is challenging. Computational reconstruction from scattered signals is used frequently. An international team of researchers (China, Saudi Arabia) has experimentally demonstrated reconstruction-free real-time imaging of static and moving objects with their actual orientation information under single-wavelength and white light illumination. They proposed a modified speckle autocorrelation imaging (SAI) method inspired by the self-imaging results. According to the researchers their strategy does not requires pre-calibration or acquisition of point-spread-function, active control of wavefronts, complicated equipment, iterations or carefully adjusted parameters. The work could pave the way towards rapid and high-quality imaging through scattering […]
Category Archives: Imaging technology
Engineers develop a low-cost, quantum-dot-enhanced terahertz camera
Nanowerk November 5, 2022 The currently available THz detectors are limited in many aspects of their performance, including sensitivity, speed, bandwidth, and operating temperature. Most do not allow the characterization of THz polarization states. The recent observation of THz-driven luminescence in quantum dots offers a possible detection mechanism via field-driven interdot charge transfer. An international team of researchers (USA – MIT, University of Minnesota, , Stanford University, SLAC National Accelerator Laboratory, South Korea) has demonstrated a room-temperature CMOS THz camera and polarimeter based on quantum-dot-enhanced THz-to-visible upconversion mechanism with optimized luminophore geometries and fabrication designs. Besides broadband and fast responses, […]
Seeing clearly into a new realm—researchers prototype a new generation of quantum microscopy
Phys.org November 7, 2022 Quantum microscopes for probing material properties and physical processes have relied on quantum defects hosted in rigid, three-dimensional (3D) crystals such as diamond, limiting their ability to closely interface with the sample. An international team of researchers (Australia, China) built a prototype quantum microscope embedding point defects within a thin layer of the van der Waals material hexagonal boron nitride. To show the multi-modal capabilities of this platform, they assembled two different heterostructures of a van der Waals material in combination with a quantum-active boron nitride flake and demonstrated time-resolved, simultaneous temperature and magnetic imaging near […]
Overcoming the optical resolution limit
Phys.org November 1, 2022 When measuring with light, the lateral extent of the structures that can be resolved by an optical imaging system is fundamentally diffraction limited. Researchers in Germany have developed an approach that uses microspheres placed directly on the surface of the object to extend the limits of interferometric topography measurements for optical resolution of small structures. They identified microspheres and photonic nanojets to explain the resolution enhancement. They extended the model with respect to microsphere-assisted interference microscopy providing a rigorous simulation of the scattered electric field directly above the sphere. Simulation and experimental results were compared in […]
MIT engineers build a battery-free, wireless underwater camera
MIT News September 26, 2022 Existing methods for underwater imaging are unsuitable for scalable, long-term, in situ observations because they require tethering for power and communication. Researchers at MIT have developed an underwater backscatter imaging, a method for scalable, real-time wireless imaging of underwater environments using fully submerged battery-free cameras that power up from harvested acoustic energy, capture color images using ultra-low-power active illumination and a monochrome image sensor and communicate wirelessly at net-zero-power via acoustic backscatter. They demonstrated wireless battery-free imaging of animals, plants, pollutants, and localization tags in enclosed and open-water environments. The method’s self-sustaining nature makes it […]
New imaging method reveals concealed objects
Phys.org July 20, 2021 Most conventional methods used to image objects behind an obstruction use ultra-short pulses in visible or infrared range. Researchers at NIST developed a method using submillimeter range, ranging from 300 micrometers up to 1 millimeter. In this range walls made of a variety of materials appear relatively smooth and act as partial mirrors, reflecting rather than diffusely scattering into view radiation from a concealed object. They used a curved mirrors to focus the invisible light. The prototype technique employed state-of-the-art indium phosphide transistors, which amplify submillimeter radiation with little noise over a wide range of wavelengths. […]
Novel imaging method developed for fast-moving objects
Phys.org July 5, 2022 When single-pixel imaging (SPI) is applied to imaging the dynamic object, severe motion blur in the restored image tends to appear. Researchers in China used a small amount of information detected by the single-pixel detector to locate and track the moving targets. With the increase of detection information over time, imaging of fast-moving objects and motion blur correction were realized synchronously. The technology fully exploits the characteristics of single-pixel detection and realizes rapid positioning, clear imaging, and recognition of fast-moving targets according to the characteristics of the system’s detection information data stream. The proposed technology roadmaps […]
Autonomous underwater imaging: Faster and more accurate
Science Daily May 26, 2022 Many modern imaging sensors must obtain multiple looks or “views” of a target at different orientations to automatically classify it with high confidence. Therefore, when tasked with classifying many targets, a mobile sensor may need to travel a long distance to change its position and orientation relative to every target, resulting in costly and time-consuming operations. A team of researchers in the US (Cornell University, Naval Surface Warfare Center) has developed a new approach, referred to as informative multiview planning (IMVP) that simultaneously determines the most informative sequence of views and the shortest path between […]
Researchers develop glass-in-glass fabrication approach for making miniature IR optics
Phys.org April 7, 2022 Glass that transmits IR wavelengths is essential for many applications. However, infrared glasses are difficult to manufacture, fragile and degrade easily in the presence of moisture. Researchers in Switzerland have developed a new technique where they created an arbitrarily shaped 3D cavity inside a fused silica glass substrate using femtosecond laser-assisted chemical etching. They used a miniaturized version of pressure-assisted casting, in which a second material was melted and pressurized so that it could flow and solidify within the network of carved silica cavities. The second material can be a metal, glass, or any material with […]
Ultrafast imaging of terahertz electric waveforms using quantum dots
Phys.org January 4, 2022 Only few imaging schemes can resolve sub-wavelength fields in the THz range, such as scanning-probe techniques, electro-optic sampling, and ultrafast electron microscopy. The intrinsic constraints on sample geometry, acquisition speed and field strength limit their applicability. An international team of researchers (Germany, Australia) harnessed the quantum-confined Stark-effect to encode ultrafast electric near-fields into colloidal quantum dot luminescence. Their approach, termed Quantum-probe Field Microscopy (QFIM), combines far-field imaging of visible photons with phase-resolved sampling of electric waveforms. By capturing ultrafast movies, they spatio-temporally resolved a Terahertz resonance inside a bowtie antenna and unveiled the propagation of a […]