Photonics/Optics

ORCA Prototype Ready to Observe Ocean

If selected for a NASA flight mission, the Ocean Radiometer for Carbon Assessment (ORCA) instrument will study microscopic phytoplankton, the tiny green plants that float in the upper layer of the ocean and make up the base of the marine food chain.Conceived in 2001 as the next technological step forward in observing ocean color, the ORCA-development team used funding from Goddard’s Internal Research and Development program and NASA’s Instrument Incubator Program (IIP) to develop a prototype. Completed in 2014, ORCA now is a contender as the primary instrument on an upcoming Earth science mission.The ORCA prototype has a scanning telescope designed to sweep across 2,000 kilometers (1,243 miles) of ocean at a time. The technology collects light reflected from the sea surface that then passes through a series of mirrors, optical filters, gratings, and lenses. The components direct the light onto an array of detectors that cover the full range of wavelengths.Instead of observing a handful of discrete bands at specific wavelengths reflected off the ocean, ORCA measures a range of bands, from 350 nanometers to 900 nanometers at five-nanometer resolution. The sensor will see the entire rainbow, including the color gradations of green that fade into blue. In addition to the hyperspectral bands, the instrument has three short-wave infrared bands that measure specific wavelengths between 1200 and 2200 nanometers for atmospheric applications.The NASA researchers will use ORCA to obtain more accurate measurements of chlorophyll concentrations, the size of a phytoplankton bloom, and how much carbon it holds. Detecting chlorophyll in various wavelengths also will allow the team to distinguish between types of phytoplankton. Suspended sediments in coastal regions could also be detected by the instrument.SourceAlso: Learn about a Ultra-Low-Maintenance Portable Ocean Power Station.

Posted in: News, Optics, Photonics, Sensors, Measuring Instruments

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Algorithm for Estimating PRC Wavefront Errors from Shack-Hartmann Camera Images

Phase retrieval is used for the calibration and the fine-alignment of an optical system. NASA’s Jet Propulsion Laboratory, Pasadena, California Phase retrieval (PR) and Shack-Hartmann Sensor (SHS) are the two preferred methods of image-based wavefront sensing widely used in various optical testbeds, adaptive optical systems, and ground- and space-based telescopes. They are used to recover the phase information of an optical system from defocused point source images (PR) and focused point source or extended scene images (SHS). For example, the Terrestrial Planet Finder Coronagraph’s (TPF-C’s) High-Contrast Imaging Testbed (HCIT) uses a PR camera (PRC) to estimate, and subsequently correct, the phase error at the exit pupil of this optical system. Several other test-beds at JPL were, and will be, equipped with both a PRC and a Shack-Hartmann camera (SHC).

Posted in: Briefs, TSP, Cameras, Optics, Sensors

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Photo-Thermo-Refractive Glass Co-Doped with Luminescent Agents for All-Solid-State Microchip Lasers

Goddard Space Flight Center, Greenbelt, Maryland A proposed solid-state technology possesses photosensitivity that enables volume hologram recording and a high efficiency of luminescence, enabling stimulated emission. These features were used to record volume Bragg gratings and to demonstrate lasing under laser diode pumping for the same volume of glass. Moreover, a combination of dopants provides extremely wide luminescence bands, which enables both wideband optical processing and extremely short laser pulse generation. It is important that the whole design be incorporated in a single, monolithic piece of glass that excludes the opportunity for misalignment and sensitivity to vibrations. If developed, the compactness and reliability of such laser devices would find wide use in space or aeronautical applications.

Posted in: Briefs, TSP, Lasers & Laser Systems, Optics

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Large Computer-Generated Hologram with Software-Generated Calibration Wavefront Map

This type of testing aspheric surfaces provides better imaging, lower mapping distortion, and much higher-quality substrates. Marshall Space Flight Center, Alabama This technology enables accurate calibration of a large Computer Generated Hologram (CGH) fabricated without great accuracy, such that the CGH still measures an aspheric surface to an excellent accuracy of a couple of nm rms. The goal is the creation of software for generating a calibration map, and the fabrication of a couple of 9-in. (≈22.5-cm)-diameter CGHs to experimentally verify the technology. Use of CGHs in testing aspheric surfaces provides many advantages, such as better imaging, lower mapping distortion, and much higher-quality substrates.

Posted in: Briefs, Optics, Electronics & Computers

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Google Glass for Industrial Automation

A new concept uses Google Glass for operating machinery, with all of the benefits delivered by wearable computing in an industrial environment. With Google’s Web-enabled glasses, status or dialog messages can be projected via a head-up display directly into a person’s field of vision. Online information and communication is also possible with this innovative device, and error messages can be acknowledged using a touchpad.

Posted in: Articles, Optics, Machinery & Automation

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New Navigation Software Cuts Self-Driving Car Costs

A new software system developed at the University of Michigan uses video game technology to help solve one of the most daunting hurdles facing self-driving and automated cars: the high cost of the laser scanners they use to determine their location.Ryan Wolcott, a U-M doctoral candidate in computer science and engineering, estimates that the new concept could shave thousands of dollars from the cost of these vehicles. The technology enables them to navigate using a single video camera, delivering the same level of accuracy as laser scanners at a fraction of the cost."The laser scanners used by most self-driving cars in development today cost tens of thousands of dollars, and I thought there must be a cheaper sensor that could do the same job," he said. "Cameras only cost a few dollars each and they're already in a lot of cars. So they were an obvious choice."Wolcott's system builds on the navigation systems used in other self-driving cars that are currently in development, including Google's vehicle. The navigation systems use three-dimensional laser scanning technology to create a real-time map of their environment, then compare that real-time map to a pre-drawn map stored in the system. By making thousands of comparisons per second, they are able to determine the vehicle's location within a few centimeters.The software converts the map data into a three-dimensional picture much like a video game. The car's navigation system can then compare these synthetic pictures with the real-world pictures streaming in from a conventional video camera.SourceAlso: See more Software tech briefs.

Posted in: News, Cameras, Lasers & Laser Systems, Photonics

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Technology Diagnoses Brain Damage from Concussions, Strokes, and Dementia

New optical diagnostic technology developed at Tufts University School of Engineering promises new ways to identify and monitor brain damage resulting from traumatic injury, stroke, or vascular dementia in real time and without invasive procedures.

Posted in: News, Electronic Components, Diagnostics, Fiber Optics, Optics, Photonics, Measuring Instruments

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