Special Coverage


3D Machine Vision Using Laser Triangulation

Applications for 3D machine vision are rapidly expanding in a variety of industries for several reasons. The first is that vision systems can lower production costs by increasing yields and/or reducing scrap product and wasted raw material. One example of this would be extruded products from various materials (rubber, plastic, metal), where it’s vital to know as soon as the process goes out of specification.

Posted in: Application Briefs, Articles, Applications, Photonics


Hyperspectral Sensing for Defense and Security Applications

The successful exploitation of hyperspectral imaging sensors depends on the availability of accurate and complete spectral signature libraries. Coupled with the appropriate spectral signature library, images collected with hyperspectral sensors provide the means to survey large areas identifying and characterizing materials, detecting a wide range of camouflaged targets, and detecting disturbed surfaces.

Posted in: Articles, Features, Photonics


Domain-Engineered Magnesium-Oxide-Doped Lithium Niobate for Lidar-Based Remote Sensing

Current work provides a path to the development of compact, single-frequency, spectroscopically useful laser sources. Goddard Space Flight Center, Greenbelt, Maryland There are several frequency conversion applications associated with lidar-based remote sensing that would benefit from the use of high-quality, complex (i.e., chirped, multi-section, or otherwise modulated) domain-engineered magnesiumoxide- doped lithium niobate (MgO:LN). While congruently melting lithium niobate (CLN) has been explored in detail over the last decades, it is known to be highly susceptible to photorefractive damage, which has limited the achievable performance of some QPM-assisted (quasi phase matching) structures that are commercially available. The demand for high-performance engineered nonlinear optical (NLO) materials, in terms of power handling, efficiency, conversion bandwidth, and accessible wavelength range, has driven the development of high-quality, large-area wafers of MgO:LN. While commercial outlets for these materials exist, there is still a need to expand the achievable performance of these structures (i.e. larger aperture bulk structures, higher efficiency waveguide structures, and implementation of sophisticated poling designs that increase achievable conversion bandwidths).

Posted in: Briefs, Tech Briefs, Photonics


Fiber-Optic Sensor for Aircraft and Structure Lightning Measurement

Langley Research Center, Hampton, Virginia An optical-fiber sensor based on Faraday Effect was developed for measuring total lightning current. Designed for aircraft installation, it is lightweight, non-conducting, structure conforming, and is immune to electromagnetic interference, hysteresis, and saturation. It can also be used on windmills, lightning towers, and can help validate lightning detection network measurements.

Posted in: Briefs, TSP, Tech Briefs, Photonics


Generating Broadband Terahertz Radiation from Microplasma in Air

Researchers at the University of Rochester’s Institute of Optics have shown that a laser-generated microplasma in air can be used as a source of broadband terahertz radiation. Fabrizio Buccheri and Xi-Cheng Zhang recently demonstrated that an approach for generating terahertz waves using intense laser pulses in air – first pioneered in 1993 – can be done with much lower power lasers, a major challenge until now.

Posted in: Articles, Briefs


Enhancing Neutron Imaging with Grazing Incidence Optics

Marshall Space Flight Center, Alabama A low-cost optical element was developed specifically for neutron optics applications. The technology operates as a reflective lens — similar to proven grazing incidence optics used for x-ray imaging — and improves neutron imaging resolution for applications using low-energy (<1 electron volt) neutrons.

Posted in: Briefs, Optics


Motion Blur Evaluation Techniques

These techniques model human sensitivity to moving spatial patterns to evaluate and improve display performance. Ames Research Center, Moffett Field, California Motion blur results when a moving edge travels across a display, such as a liquid crystal display (LCD), that has limited temporal response. It is important to be able to quantify this effect in visual terms. The techniques described in this work provide methods for estimating the strength of the motion blur artifact in perceptual units of JNDs (just noticeable differences).

Posted in: Briefs, Optics