Photonics

Adaptive Zoom Riflescope Prototype Has Push-Button Magnification

When an Army Special Forces officer‑turned engineer puts his mind to designing a military riflescope, he doesn’t forget the importance of creating something for the soldiers who will carry it that is easy to use, extremely accurate, light‑weight and has long‑lasting battery power. The result is the Rapid Adaptive Zoom for Assault Rifles (RAZAR) prototype, developed by Sandia National Laboratories optical engineer Brett Bagwell. At the push of a button, RAZAR can toggle between high and low magnifications, enabling soldiers to zoom in without having to remove their eyes from their targets or their hands from their rifles.

Posted in: Photonics, Optics, Defense, News

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Researchers Measure Stress in 3D-Printed Metal Parts

Lawrence Livermore National Laboratory researchers have developed an efficient method to measure residual stress in metal parts produced by powder-bed fusion additive manufacturing (AM).The 3D-printing process produces metal parts layer by layer using a high-energy laser beam to fuse metal powder particles. When each layer is complete, the build platform moves downward by the thickness of one layer, and a new powder layer is spread on the previous layer.While the method produces quality parts and components, residual stress is a major problem during the fabrication process. Large temperature changes near the last melt spot, and the repetition of this process, result in localized expansion and contraction.An LLNL research team, led by engineer Amanda Wu, has developed an accurate residual stress measurement method that combines traditional stress-relieving methods (destructive analysis) with modern technology: digital image correlation (DIC). The process provides fast and accurate measurements of surface-level residual stresses in AM parts.The team used DIC to produce a set of quantified residual stress data for AM, exploring laser parameters. DIC is a cost-effective, image analysis method in which a dual camera setup is used to photograph an AM part once before it’s removed from the build plate for analysis and once after. The part is imaged, removed, and then re-imaged to measure the external residual stress.SourceAlso: Learn about Design and Analysis of Metal-to-Composite Nozzle Extension Joints.

Posted in: Cameras, Imaging, Photonics, Lasers & Laser Systems, Manufacturing & Prototyping, Rapid Prototyping & Tooling, Materials, Metals, Test & Measurement, Measuring Instruments, News

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Supersonic Laser-Propelled Rockets Could Help Aircraft Exceed Mach 10

A new method for improving the thrust generated by laser-propulsion systems may bring them one step closer to practical use. The method, developed by physicists Yuri Rezunkov of the Institute of Optoelectronic Instrument Engineering, Russia, and Alexander Schmidt of the Ioffe Physical Technical Institute in Saint Petersburg, Russia, integrates a laser‑ablation propulsion system with the gas‑blasting nozzles of a spacecraft. Combining the two systems can increase the speed of the gas flow out of the system to supersonic speeds, while reducing the amount of burned fuel.

Posted in: Photonics, Lasers & Laser Systems, Motion Control, Power Transmission, Aerospace, Aviation, News

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NASA Technologists Advance Next-Generation 3D Imaging

Building, fixing, and refueling space-based assets or rendezvousing with a comet or asteroid will require a robotic vehicle and a super-precise, high-resolution 3D imaging lidar that generates the real-time images needed to guide the vehicle to a target traveling at thousands of miles per hour.A team of technologists at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is developing a next-generation 3D scanning lidar — dubbed the Goddard Reconfigurable Solid-state Scanning Lidar (GRSSLi) — that could provide the imagery required to execute these orbital dances.Equipped with a low-power, eye-safe laser, a micro-electro-mechanical scanner, and a single photodetector, GRSSLi will "paint" a scene with the scanning laser. Its detector will sense the reflected light to create a high-resolution 3-D image at kilometer distances — a significant increase in capability over current imaging lidars that are effective only at meter distances.Just as important, the instrument is equipped with onboard "vision" algorithms that interpret the three-dimensional image returned by the lidar. The softwar estimates location and attitude of a target relative to the lidar.SourceAlso: Learn about NASA's Asteroid Redirect Mission.

Posted in: Visualization Software, Imaging, Photonics, Lasers & Laser Systems, Aerospace, RF & Microwave Electronics, News

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Light Bending Material Facilitates Search for New Particles

Particle physicists have a hard time identifying all the elementary particles created in their particle accelerators. But now researchers at Chalmers University of Technology have designed a material that makes it much easier to distinguish the particles.

Posted in: Photonics, Optics, Materials, Solar Power, Energy, News

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Scientists Find Novel Way to Improve Laser Performance

Energy loss in optical systems, such as lasers, is a chief hindrance to their performance and efficiency and it occurs on an ongoing, frustrating basis. To help laser systems overcome loss, operators often pump the system with an overabundance of photons, or light packets, to achieve optical gain. But now, scientists from the School of Engineering & Applied Science at Washington University in St. Louis have shown a new way to reverse or eliminate such loss by, ironically, adding loss to a laser system to actually reap energy gains. In other words, they've invented a way to win by losing.

Posted in: Photonics, Fiber Optics, Lasers & Laser Systems, Optics, Optical Components, News

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NASA Team Proposes Laser for Orbital Debris Tracking

Barry Coyle and Paul Stysley, laser researchers at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, want to develop a method to define and track orbital debris using laser ranging — a promising approach that could overcome shortfalls with passive optical and radar techniques, which debris trackers use today to locate and track dead satellites, spacecraft components, and other remnants orbiting in low-Earth or geosynchronous orbits where most space assets reside.Inspired by an Australian study that found laser tracking increased the accuracy of debris ranging by a factor of 10 when compared with other methods, Coyle and Stysley now "want to reproduce the results from this paper on a larger scale," using Goddard’s Geophysical and Astronomical Observatory (GGAO). The GGAO satellite laser-ranging team, led by Goddard’s Jan McGarry, has advanced laser-ranging techniques using satellites equipped with retro-reflectors, becoming world leaders in the field.GGAO’s 48-inch telescope, which transmits outgoing and receives incoming laser beams, was built in the early 1970s as a research and development and testing facility for laser ranging, lidar, and astronomical instruments. The facility has ranged to spacecraft at planetary distances and has been used to provide on-orbit calibration of some of Goddard’s altimetry spacecraft. NASA also used the facility in 2005 to determine the performance of the laser-altimeter instrument aboard its MESSENGER spacecraft as it flew past Earth during its sojourn to Mercury.Once the team demonstrates ranging with a target not equipped with the retro-reflector, it would like to implement the technique in a global network of ground-based laser observatories to observe and more accurately track debris, thus aiding the world’s current debris-tracking efforts.Although it’s difficult removing the material itself, NASA mission operators can minimize its impact on operational space assets. They can move non-operational spacecraft to less populated orbits to remove the threat to new missions or allow dead craft to re-enter the atmosphere, where they burn up upon entry. What’s essential is that these assets are tracked and monitored to protect active and future missions from potentially harmful collisions, Coyle said.SourceAlso: Learn about a Debris & Ice Mapping Analysis Tool.

Posted in: Photonics, Lasers & Laser Systems, Aerospace, RF & Microwave Electronics, News

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