optics (4)

Touchless Print Scanning...

Credit: N. Hanacek/NIST NIST evaluated several commercially available contactless fingerprint scanning technologies in its May 2020 report.


Topics: NIST, Optics, Research

The National Institute of Standards and Technology (NIST) has evaluated several commercially available contactless fingerprint scanning technologies, allowing users to compare their performance to conventional devices that require physical contact between a person’s fingers and the scanner.

The results of the study, published today as NIST Interagency Report (NISTIR) 8307: Interoperability Assessment 2019: Contactless-to-Contact Fingerprint Capture, show that devices requiring physical contact remain superior to contactless technology at matching scanned prints to images in a database. However, when contactless devices scan multiple fingers on a hand, it improves their performance. Contactless devices that scanned multiple fingers also seldom made “false positive” errors that incorrectly matched one person’s print with another’s record.

The publication updates NIST’s July 2018 study on contactless capture and is intended to assist organizations that use fingerprint-scanning technology.

“The report summarizes the state of the art of contactless fingerprint scanning,” said John Libert, one of the report’s authors. “It can help anyone interested in adopting contactless technology to evaluate the cost in performance they might pay by switching to contactless fingerprint capture.”

NIST Study Measures Performance Accuracy of Contactless Fingerprinting Tech

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Silicon Sees the Light...

Silicon sees the light: Elham Fadaly (left) and Alain Dijkstra in their Eindhoven lab. (Courtesy: Sicco van Grieken/SURF)


Topics: Optics, Electrical Engineering, Nanotechnology, Research, Solar Power, Spectroscopy

A light-emitting silicon-based material with a direct bandgap has been created in the lab, fifty years after its electronic properties were first predicted. This feat was achieved by an international team led by Erik Bakkers at Eindhoven University of Technology in the Netherlands. They describe the new nanowire material as the “Holy Grail” of microelectronics. With further work, light-emitting silicon-based devices could be used to create low-cost components for optical communications, computing, solar energy and spectroscopy.

Silicon is the wonder material of electronics. It is cheap and plentiful and can be fabricated into ever smaller transistors that can be packed onto chips at increasing densities. But silicon has a fatal flaw when it comes to being used as a light source or solar cell. The semiconductor has an “indirect” electronic bandgap, which means that electronic transitions between the material’s valence and conduction bands involve vibrations in the crystal lattice. As a result, it is very unlikely that an excited electron in the conduction band of silicon will decay to the valence band by emitting light. Conversely, the absorption of light by silicon does not tend to excite valence electrons into the conduction band – a requirement of a solar cell.


Silicon-based light emitter is ‘Holy Grail’ of microelectronics, say researchers
Hamish Johnston, Physics World

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Hologram Printer...

The new printer uses low-power continuous wave lasers to create holograms on a highly sensitive photomaterial developed by the researchers. Credit: C Yves GENTET


Topics: 3D Objects, 3D Printing, Applied Physics, Holograms, Optics, Research

Researchers have developed a new printer that produces digital 3-D holograms with an unprecedented level of detail and realistic color. The new printer could be used to make high-resolution color recreations of objects or scenes for museum displays, architectural models, fine art or advertisements that do not require glasses or special viewing aids.

"Our 15-year research project aimed to build a hologram printer with all the advantages of previous technologies while eliminating known drawbacks such as expensive lasers, slow printing speed, limited field of view and unsaturated colors," said research team leader Yves Gentet from Ultimate Holography in France. "We accomplished this by creating the CHIMERA printer, which uses low-cost commercial lasers and high-speed printing to produce holograms with high-quality color that spans a large dynamic range."


New printer creates extremely realistic colorful holograms, The Optical Society, Phys.org

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How We See the Small...

View of cantilever on an atomic force microscope (magnification 1000x).
Credit: SecretDisc GFDL, CC-BY-SA-3.0


Topics: Atomic Force Microscopy, Nanotechnology, Optics, Scanning Electron Microscope

Cell reproduction, disease detection and semiconductor optimization are just some of the areas of research that have exploited the atomic force microscope. First invented by Calvin Quate, Gerd Binnig and Christoph Gerber in the mid 1980s, atomic force microscopy (AFM) brought the atomic resolution recently achieved by the scanning tunnelling microscope to non-conducting samples, and helped to catalyse the avalanche of science and technology based on nanostructures that now permeates all aspects of modern life from smartphones to tennis rackets. On 6 July 2019 Calvin Quate died aged 95 at his home in Menlo Park, California.

Long before the development of AFM, Quate’s research had made waves in microscopy. 1978 had seen the announcement of the scanning acoustic microscope, which achieved the sensitivity of optical microscopy but probed samples so softly that it could image the interiors of living cells without damaging them. The technique uses high frequency sound waves in place of light, which penetrate deep into structures to image internal structures non-destructively. It is widely used in quality control of electronic component assembly among other applications such as printed circuit boards and medical products.

Advanced microscopy pioneer leaves broad ranging legacy
Anna Demming, Physics World

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