New optical system could lead to devices that can recognize objects instantly

Technology.org  March 5, 2020 Diffractive optical network is a recently introduced optical computing framework that merges wave optics with deep-learning methods to design optical neural networks. Previous diffractive approaches employed monochromatic coherent light as the illumination source. Researchers at UCLA designed a broadband diffractive optical neural network that simultaneously processes a continuum of wavelengths generated by a temporally incoherent broadband source to all-optically perform a specific task learned using deep learning. They fabricated and tested seven different multi-layer, diffractive optical systems that transform the optical wavefront generated by a broadband THz pulse to realize a series of tunable, single-passband and […]

Lasers and terahertz waves combined in camera that sees ‘unseen’ detail

Science Daily  February 18, 2020 The core challenge in THz cameras is not about collecting an image, but preserving the objects spectral fingerprint that can be easily corrupted by the technique. Researchers in the UK used a single-pixel camera to image sample objects with patterns of THz light. The prototype they built can detect how the object alters different patterns of THz light. By combining this information with the shape of each original pattern the camera reveals the image of an object as well as its chemical composition. The camera creates THz electromagnetic waves very close to the sample, similar […]

Using long-wavelength terahertz radiation to produce video with a high frame rate

Phys.org  February 10, 2020 Long-wavelength terahertz radiation which is considered to be much safer than X-ray radiation has not been used in security and medical devices because its energy is so low and it has been difficult to create high-resolution images using them. Instead of building a more sensitive sensor researchers in the UK made the waves more readable to conventional technology. They converted the terahertz radiation into green light by directing it into a cloud of excited cesium atoms. Once the cloud was formed, the researchers fired a secondary terahertz laser through a moving object, which allowed a “shadow […]

Army wants tech that can identify people through walls

Fedscoop  January 30, 2020 A new request for information is soliciting white papers on portable technology that can detect, identify, and monitor persons, animals, and materials behind multi-leveled obstruction(s) from a long standoff range, a technology that works both in the city and that can be deployed in dense foliage. The ideal system should be able to read biometric data, perform knowledge management functions and use machine learning and artificial intelligence to improve its science-fiction-like vision powers. Army is looking for information about technology that is ready to be used. Whether any such exists is uncertain. While wall-penetrating technology has […]

How to take a picture of a light pulse

Phys.org  January 27, 2020 Measuring the shape of the laser light wave with high accuracy required for investigating materials to medical diagnostics requires a large, complex experimental setup. In their experiment an international team of researchers (Germany, Austria) hit a tiny crystal of silicon oxide with the laser pulse to be investigated. While this laser pulse penetrates the crystal, another strong infrared pulse is fired at the target changing the energy state of the electrons so that they become mobile. As soon as the electrons can move through the crystal, they are accelerated by the electric field of the first […]

Deep learning enables real-time imaging around corners

Science Daily  January 16, 2020 A team of researchers in the US (Stanford University, Princeton University, Southern Methodist University, Rice University) developed an imaging system which uses a commercially available camera sensor and a powerful laser source that is similar to the one found in a laser pointer. The laser beam bounces off a visible wall onto the hidden object and then back onto the wall, creating a speckle pattern that encodes the shape of the hidden object. It can distinguish submillimeter details of a hidden object from 1 meter away. The system can be combined with other imaging systems […]

Ultrafast camera takes 1 trillion frames per second of transparent objects and phenomena

Phys.org  January 20, 2020 Researchers at Caltech have developed a new imaging system, phase-sensitive compressed ultrafast photography (pCUP), that combines with phase-contrast microscopy, that was designed to allow better imaging of objects that are mostly transparent such as cells. They adapted the standard phase-contrast microscopy so that it provides very fast imaging. The system consists of lossless encoding compressed ultrafast technology (LLE-CUP) which takes a single shot, capturing all the motion that occurs during the time that shot takes to complete. LLE-CUP is capable of capturing motion, such as the movement of light itself. They demonstrated the capabilities of pCUP […]

Researchers capture moving object with ghost imaging

Science Daily  November 13, 2019 Ghost imaging has been limited to stationary objects because it takes a long time to project the sequence of light patterns onto the object that is necessary to reconstruct an image making blurry. The ghost imaging technique forms an image by correlating a beam that interacts with the object and a reference beam that does not interact with te object. Individually, the beams don’t carry any meaningful information about the object. To apply ghost imaging to moving objects researchers in China used a small number of light patterns to capture the position and trajectory of […]

Extracting hidden quantum information from a light source

Phys.org  October 24, 2019 An international team of researchers (UK, USA – Princeton University) experimentally demonstrated the distillation of a quantum image from measured data composed of a superposition of both quantum and classical light. They measured the image of an object formed under quantum illumination that is mixed with another image produced by classical light with the same spectrum and polarization, and demonstrated near-perfect separation of the two superimposed images by intensity correlation measurements. This work provides a method to mix and distinguish information carried by quantum and classical light, which may be useful for quantum imaging, communications, and […]

New chip poised to enable hand-held microwave imaging

Science Daily  September 26, 2019 Researchers at the University of Pennsylvania used a standard semiconductor fabrication process to make a microwave imager chip, measuring just over 2 millimeters on each side, containing more than 1,000 photonic components. The imager uses four antennas to receive microwave signals reflected from an object. The microwave signals are then encoded into an optical signal and are optically processed to form an image. To demonstrate the new chip, the researchers used it to image objects with metallic surfaces. The system is significantly smaller and more efficient than its electronic equivalent and can operate with significantly […]