Photonics/Optics

Compact, Lightweight, Athermal, Nanocomposite Telescopes with Freeform Optics

Marshall Space Flight Center, Alabama Small space missions such as CubeSats frequently require telescopes with highly sophisticated optical systems that are also low in mass and cost. The very limited spacecraft volume and mass limits also preclude adjustments to maintain critical alignment with change in temperature. Existing systems, especially those that employ folded optical paths with freeform optics, are expensive to fabricate. The optics, and support and metering structures, are also heavy due to the use of high-density material such as glass, aluminum, or nickel.

Posted in: Briefs, Tech Briefs, Imaging, Photonics, Optics, Composite materials, Nanomaterials, Satellites

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One-Micron (1064-nm) Planar External Cavity Laser (PLANEX)

Goddard Space Flight Center, Greenbelt, Maryland A highly reliable, very low-phase and low-amplitude-noise laser is required as an oscillator for the LISA mission. A commercial product made by Redfern Integrated Optics met these requirements (1550 nm PLANEX External Cavity Laser), but it operated at 1.5 microns, not the required LISA wavelength of 1 micron. An ultra-low-noise External Cavity Laser was produced at a wavelength of 1 micron, and was integrated in a butterfly package. The goal is to eventually use this laser in the LISA and GRACE-II missions.

Posted in: Briefs, Tech Briefs, Imaging, Photonics, Lasers, Product development, Packaging

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Invertible Time Invariant Linear Filtering (InTILF) Method for Pattern Detection and Modeling of Stochastic One- or Two- Dimensional Data

This tool can analyze and model surface metrology data for polishing-tool fabricators. Marshall Space Flight Center, Alabama X-ray astronomy offers the opportunity to observe important phenomena, including the early accretion of massive black holes and detecting diffuse ionized intergalactic gas that is heated to X-ray temperatures (>106). One of the technical challenges facing X-ray astronomy is fabricating optics that are properly shaped and smooth enough to produce quality images. Surface defects on the order of the wavelength of the observed spectrum and up to the size of the optical surface must be polished out of the mirrors without leaving a de - tectable pattern because the detectable signal is on the order of magnitude of the noise. This leads to a cycle of polishing and metrology that adds time and expense to optics fabrication.

Posted in: Briefs, Tech Briefs, Imaging, Photonics, Mirrors, Optics, Metal finishing

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3D Imaging Reveals Battery Degradation in Real Time

Using sophisticated 3D imaging, a team at University College London, The European Synchrotron (ESRF), University of Manchester, Harwell Oxford, Oregon State University, and the National Physical Laboratory visualized a battery’s performance loss and internal structural damage. The images of active commercial Li/MnO2 disposable batteries, captured using X-ray computed tomography, will help to improve cell designs.

Posted in: Articles, Features, Imaging, Photonics, Batteries, Imaging and visualization, Performance tests

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Filtering in Machine Vision

There are many different types of filters in machine vision that can be utilized to improve or change the image of the object under inspection. It is important to understand the different technologies behind the various types of filters in order to understand their advantages and limitations. Although there is a wide variety of filters, almost all can be divided into two primary categories: colored glass filters and coated filters.

Posted in: Articles, Features, Imaging, Photonics, Imaging and visualization, Optics, Automation, Glass

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Customized Drone Maps Glaciers

Using a custom-designed drone, a researcher from The Ohio State University mapped glaciers and wetlands in Peru’s Cordillera Blanca mountain range. Despite a discovered drop in glacier growth, the findings from the unmanned aerial vehicle (UAV) revealed a slightly more optimistic picture of the region’s water supply, which relies in part on the ice formations.

Posted in: Application Briefs, Applications, Imaging, Photonics, Cartography, Terrain, Water, Unmanned aerial vehicles

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Continental-Scale Mapping of Adélie Penguin Colonies from Landsat Imagery

Remote sensing is used for biological conservation. Goddard Space Flight Center, Greenbelt, Maryland The Adélie penguin has a circum-Antarctic distribution and is widely considered a useful indicator of status and change in the Antarctic and Southern Ocean ecosystems. Breeding distribution of the Adélie penguin was surveyed with Landsat-7 Enhanced Thematic Mapper Plus (ETM+) over the entire continent of Antarctica. An algorithm was designed to minimize radiometric noise and to retrieve Adélie penguin colony location and spatial extent from the ETM+ data. In all, 259 ETM+ scenes were selected from the Lansdat archive from the 1999–2003 era and were used in the retrieval. Pixel clustering identified a total of 244 individual Adélie penguin colonies, ranging in size from a single pixel (900 m2) to a maximum of 875 pixels (0.788 km2). The Landsat retrievals successfully located Adélie penguin colonies that accounted for ≈96 to 97% of the regional population used as ground truth, with errors of omission and commission on the order of only 1 to 2%.

Posted in: Briefs, Tech Briefs, Environmental Monitoring, Imaging, Photonics, Mathematical models, Statistical analysis, Environmental testing, Weather and climate, Satellites

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