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  • Volume 47, Issue 3

    • Volume 47, Issue 3

    30573
    Detectors & Imaging

    Seeing is believing

    Stephen G. Anderson
    March 1, 2011
    Like so many other innovations, the charged coupled device (CCD) was invented at AT&T Bell Labs.
    A pillar-shaped InGaAs laser resonator has six facets (a); laser light follows a helical path down the pillar into the Si substrate (b).
    Lasers & Sources

    SILICON PHOTONICS: Nanopillar lasers are grown on silicon

    Jeff Hecht
    March 1, 2011
    Successful growth of nanopillar III-V lasers on silicon (Si) by Connie Chang-Hasnain's group at the University of California at Berkeley has opened a new approach to integrating...
    1304qa Chang New
    Executive Forum

    Business Forum: When and how should I borrow to increase capital?

    Milton Chang
    March 1, 2011
    To never borrow is usually the right thing to do, but companies do borrow; even established companies with substantial assets have lines of credit.
    FIGURE 1. The flux mapping method is simple to use in designing a reflector, for example, but may require discontinuities in the generated freeform surface that produce artifacts in the illuminance pattern.
    Optics

    SOFTWARE & COMPUTING: Freeform optics design advances lighting and illumination

    March 1, 2011
    Freeform optics have become ubiquitous. You most likely have one in your pocket or purse right now on your cell-phone camera module.
    Research

    IN MY VIEW: Races for the rare earths

    Jeffrey Bairstow
    March 1, 2011
    I was surprised to learn just how critical the so-called "rare earth elements" are in the development of complex electronics for the high-performance consumer and military/defense...

    More content from Volume 47, Issue 3

    (Image adapted with permission from Fuller and Millett [2], The Future of Computing Performance: Game Over or Next Level?, 2011, National Academy of Sciences, courtesy of the National Academies Press, Washington, DC)
    FIGURE 1. Single-processor performance rose steadily from 1986 until about 2004, when it abruptly leveled off. Single points show performance of individual processors at their date of introduction, as measured by the SPECint2000 benchmark test. The solid line shows the actual trend; the dashed line shows the target from the International Technology Roadmap for Semiconductors from 2009 to 2020.
    Optics

    PHOTONIC FRONTIERS: INTEGRATED PHOTONICS: Photonic integration may boost computing performance

    Jeff Hecht
    March 1, 2011
    Massive parallelism and dramatic cuts in energy budgets are crucial for the future of high-performance computing. Integrated photonics can help developers reach those goals by...
    A lithographic process for doubling the frequency of an initially created polymer grating results in an iridium wire-grid grating with a 100 nm period.
    Optics

    POLARIZATION OPTICS: Iridium makes superior wire-grid polarizer for UV

    John Wallace
    March 1, 2011
    With their large spectral range and conveniently thin platelike form, wire-grid optical polarizers work well in many types of optical systems. At one time only available for the...
    Research

    New zirconium-doped LiNbO3 crystal resists UV-to-visible damage

    John Wallace
    March 1, 2011
    Periodically poled magnesium-doped lithium niobate (LiNbO3) or PPMgLN is a commonly used crystal for laser frequency conversion using the quasi-phase-matching technique due to...
    (Courtesy of Horiba Scientific)
    In the SHI camera, a raw image (a) consists of a zero-order image that replicates the original scene surrounded by several higher diffraction orders in both directions that contain all the spatial and spectral information in the scene. The 'data cube' or hypercube (b) is generated by software reconstruction using the image in (a) as the input.
    Detectors & Imaging

    HYPERSPECTRAL IMAGING: One-shot camera obtains simultaneous hyperspectral data

    Gail Overton
    March 1, 2011
    Commercially available spectral imaging systems capture the intensity information from a scene and display it as a digital image (with x and y spatial coordinates), while also...
    FIGURE 1. The quantum efficiency curve of sCMOS cameras is now much closer to that of CCDs than that of the CMOS cameras of just a few years ago.
    Detectors & Imaging

    CHARGE-COUPLED DEVICES: CCDs lose ground to new CMOS sensors

    March 1, 2011
    While enhanced CCDs still provide important niche application performance, recent advances are enabling new CMOS imagers to address scientific applications.
    1103breaks Fig2
    Detectors & Imaging

    HgTe-HgCdTe superlattice photodetector has high response in LWIR

    Gail Overton
    March 1, 2011
    A superlattice of mercury telluride-mercury cadmium telluride (HgTe-HgCdTe) contains alternating layers of the two materials only nanometers thick; when used for IR photoconductive...
    FIGURE 1. An optical plate for a direct-diode system includes a beam-combiner enclosure and fiber-output couplings (top). Weld penetration versus welding speed for a 3 kW system is shown for two spot sizes (bottom).
    Lasers & Sources

    HIGH-POWER DIODE LASERS: Low-numerical-aperture direct diode laser maintains high power

    March 1, 2011
    A passively cooled, fiber-coupled diode module has a previously unachieved combination of high power and high beam quality.
    Research

    Infrared bolometer is inkjet-printed on flexible plastic

    John Wallace
    March 1, 2011
    Scientists at the Laboratoire de Physique des Interfaces et des Couches Minces, Ecole Polytechnique, and Thales Research and Technology (both in Palaiseau, France) are making ...
    (Courtesy of Physikalisch-Technische Bundesanstalt)
    One of two spheres used for precisely determining the Avogadro constant is made of pure enriched 28Si from a dislocation-free boule; its diameter and variations in diameter are known to an accuracy of 0.6 pm.
    Test & Measurement

    OPTICAL MATERIALS: 'Quasiperfect' Si sphere is crucial to new measurement of Avogadro constant

    John Wallace
    March 1, 2011
    The Avogadro project was started in 2003 by a consortium of measurement-standards laboratories.
    FIGURE 1. A 3D lidar sensor uses independent time-of-flight measurements at every pixel to acquire distance information for objects in the scene. Obscuring objects in the foreground (such as foliage) can be eliminated based on the distance data collected.
    Detectors & Imaging

    FOCAL-PLANE ARRAYS: Geiger-mode focal plane arrays enable SWIR 3D imaging

    March 1, 2011
    By hybridizing Geiger-mode APD arrays to suitable CMOS readout integrated circuits, a focal-plane array can be developed that serves as an ideal sensor engine for 3D imaging lidar...
    (All images courtesy of SOHO)
    FIGURE 1. The EIT recorded one hour of a coronal mass ejection at 19.5 nm on Feb. 26–27, 2000.
    Test & Measurement

    PHOTONICS APPLIED: ASTRONOMY: Photonics plays critical role in understanding our Sun

    Gail Overton
    March 1, 2011
    Data from imagers, spectrometers, and other optical sensors aboard numerous Sun-observing spacecraft are being used to understand solar flares, the source of coronal mass ejections...
    A quantum-cascade TPV structure contains an embedded grating that scatters light to maximize absorption of both TM and TE polarized light.
    Detectors & Imaging

    PHOTOVOLTAICS: Thermophotovoltaic device design has double the efficiency

    John Wallace
    March 1, 2011
    While photovoltaic (PV) cells that extract energy from sunlight are getting much attention, another type of PV device has great promise too.
    Test & Measurement

    Terahertz optical metasurface has a high Q-factor

    John Wallace
    March 1, 2011
    A metasurface (a surface patterned with periodic subwavelength-sized metallic features on dielectric) can serve as a filter in the terahertz-radiation region, or, with modifications...
    Optics

    Robust synthesis method improves dielectric-mirror design

    John Wallace
    March 1, 2011
    Many significant breakthroughs in ultrafast-laser technology have been made possible by improvements in ultrafast laser optics, specifically in the development of thin-film dielectric...
    FIGURE 1. The spectral variation in refractive index for zinc sulfide (ZnS) shows very different V-numbers (or Abbe numbers) for the SWIR, MWIR, and LWIR.
    Optics

    IR OPTICS: Ultrabroadband optics image from visible to longwave IR

    March 1, 2011
    By taking into account the "volatility" of optical dispersion, optical materials can be combined to create a single refractive lens system for imaging across the visible and infrared...