Photonics

Shortwave Infrared - The Latest Weapon in the War on Terror

Keeping one step ahead of our adversaries is top priority for security forces with terrorist threats growing daily around the world. Intelligence, surveillance and reconnaissance are the core situational awareness tools for the global war on terrorism (GWOT). Just as night vision equipment has denied terrorists the cover of darkness for more than a couple of decades, emerging shortwave infrared imaging technology is now removing weather and environmental limitations from the ISR equation.

Posted in: ptb catchall, Applications, Photonics, Application Briefs

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Specialty Fibers Guide Light When the Going Gets Tough

In spectrometry, the more light gathered the better the results. Yet in many applications, both military and commercial, the need to protect instruments or operators from harsh environments, as well as installation constraints, make conventional line-of-sight optics impractical. Specialty fibers can offer the robustness and light-handling characteristics that such applications require.

Posted in: Features, ptb catchall, Photonics, Articles

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Using Vision Sensors to Eliminate Manufacturing Defects

Supplying parts to the world’s leading automotive companies leaves no room for error. That’s why Miniature Precision Components Inc. (MPC) uses three vision sensors to error-proof the automated assembly of oil-caps at its Prairie du Chien, WI facility. With 41 molding machines ranging in size from 25 to 550 tons, this 100,000 square-foot facility employs about 450 people. MPC’s four manufacturing plants generate approximately $167 million per year supplying the automotive and commercial industries with high-quality injection-molded parts and assemblies such as PCV valves, thermostat housings, and quick-connect ports for emission control systems.

Posted in: ptb catchall, Applications, Photonics, Application Briefs

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Micromachining with Lasers

Laser micromachining involves using light to remove material. Lasers can also be used in many other applications such as welding, marking, additive manufacturing and surface alteration, but these fall outside the definition. As a general rule, laser micromachining involves working on substrates that are less than 1 mm in thickness — usually much less — and feature sizes that are also less than 1 mm, with the lower end on the order of a few microns.

Posted in: Features, ptb catchall, Photonics, Articles

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Measuring LED and Solid State Lighting Performance

Light emitting diodes (LEDs) and solid state lighting (SSL) products that incorporate LEDs pose many measurement challenges compared with other lighting elements, such as traditional tungsten and fluorescent. Advanced optical radiation measurement equipment and new techniques are often required to determine basic photo-metric and colorimetric parameters for LEDs and SSL products. Updated measurement instrumentation, calibration and performance characterization methods have allowed for improvement in the repeatability and reproducibility of measurements of average LED intensity, total luminous flux and colorimetric quantities. Lower uncertainty, detector-based standards provide a convenient transfer and monitoring from primary measurement standards.

Posted in: ptb catchall, Applications, Photonics, Application Briefs

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Metrology System for a Large, Somewhat Flexible Telescope

This system would measure focal-plane position errors caused by structural deformations. NASA’s Jet Propulsion Laboratory, Pasadena, California A proposed metrology system would be incorporated into a proposed telescope that would include focusing optics on a rigid bench connected via a deploy- able mast to another rigid bench holding a focal-plane array of photon counting photodetectors. Deformations of the deployable mast would give rise to optical misalignments that would alter the directions (and, hence, locations) of incidence of photons on the focal plane. The metrology system would measure the relative displacement of the focusing-optics bench and the focal-plane array bench. The measurement data would be used in post-processing of the digitized photodetector outputs to compensate for the mast-deformation-induced changes in the locations of incidence of photons on the focal plane, thereby making it possible to determine the original directions of incidence of photons with greater accuracy.

Posted in: Tech Briefs, ptb catchall, Photonics, Briefs

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Formation Flying of Components of a Large Space Telescope

NASA’s Jet Propulsion Laboratory, Pasadena, California A conceptual space telescope having an aperture tens of meters wide and a focal length of hundreds of meters would be implemented as a group of six separate optical modules flying in formation: a primary-membrane-mirror module, a relay-mirror module, a focal-plane-assembly module containing a fast steering mirror and secondary and tertiary optics, a primary-mirror-figure-sensing module, a scanning-electron-beam module for controlling the shape of the primary mirror, and a sunshade module. Formation flying would make it unnecessary to maintain the required precise alignments among the modules by means of an impractically massive rigid structure. Instead, a control system operating in conjunction with a metrology system comprising optical and radio sub-systems would control the firing of small thrusters on the separate modules to maintain the formation, thereby acting as a virtual rigid structure. The control system would utilize a combination of centralized- and decentralized-control methods according to a leader-follower approach.

Posted in: Tech Briefs, ptb catchall, Photonics, Briefs

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