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  • Volume 44, Issue 12

    • Volume 44, Issue 12

    Research

    Optimized tungsten photonic-crystal emitters outdo blackbodies in IR bands

    Dec. 1, 2008
    Researchers at Sandia National Laboratories and the University of New Mexico (both in Albuquerque, NM) have numerically optimized tungsten photonic-crystal (PC) thermal emitters...
    Fiber Optics

    Spiral photonic-crystal fiber design is golden

    Dec. 1, 2008
    Engineers at City University London (London, England) have demonstrated a photonic-crystal fiber (PCF) in which the air holes were laid out in a “golden spiral” (GS)–a pattern...
    Th Liquid 01
    Optics

    Liquid mirrors deform magnetically

    Dec. 1, 2008
    A unique liquid mirror has been developed by researchers at Université Laval (Quebec, QC, Canada) that combines a surface film of silver particles with a magnetic fluid.
    Test & Measurement

    Photonic structures on chipresonate with infrared quantum-dot emission

    Dec. 1, 2008
    Optical coupling of quantum dots and silicon (Si) photonic-crystal cavities may be useful as novel optical integrated light emitters that can be erased and rewritten, say scientists...
    Th Cnt 01
    Research

    CNT electrode for OLED displays is transparent and flexible

    Dec. 1, 2008
    Multiwalled carbon nanotubes (CNTs) are the basis of a transparent electrode that researchers at the University of Texas at Dallas have developed for use in high-brightness organic...

    More content from Volume 44, Issue 12

    (Courtesy of Tufts University)
    FIGURE 1. A paper in the BiOS Symposium at Photonics West shows how the biocompatible nature of silk allows seamless embedding of active optics in everyday objects. The readout is provided by the optical element, for example, as a color or image change; when something unwanted is present (such as E. coli bacteria), the color changes or the holographic images disappear.
    Research

    PHOTONICS WEST PREVIEW: Photonics West hailed as ‘essential photonics event’

    Gail Overton
    Dec. 1, 2008
    Considered by many to be the premier event of the photonics industry, Photonics West 2009 gears up for another banner year.
    The insertion loss for each of three optical fibers in a 3 × 3 visible-light multiplexer and white-light synthesizer is about 5.5 dB across a 100 nm test range.
    Lasers & Sources

    VISIBLE ILLUMINATION: Mini white-light source has tunable color temperature

    John Wallace
    Dec. 1, 2008
    The synthesis of uniform white light from separate red, blue, and green LEDs gets more difficult as the area to be illuminated gets smaller and more akin to the size of the LEDs...
    Optics

    MEDICAL OCT: Ultra-high-resolution optical coherence tomography gets adaptive-optic ‘glasses’

    Dec. 1, 2008
    Ultra-high-resolution OCT imaging that uses adaptive optics is improved with a new source and optics for clinical in vivo visibility of the human retina.
    (Courtesy of National Physical Laboratory, Crown Copyright 2008)
    A low-coherence interferometry technique uses the results from an OCT microscope to determine sample thickness at multiple angles of incidence; the thickness values are then fitted to an equation that can calculate the bulk refractive index–even for biological materials that scatter light throughout their entire depth and cannot be measured by other conventional techniques.
    Optics

    OPTICAL MEASUREMENT: OCT technique measures bulk refractive index

    Gail Overton
    Dec. 1, 2008
    Although critical-angle refractometry techniques are well-established for measuring the refractive index of homogeneous transparent materials with an uncertainty on the order ...
    (Courtesy of the University of Arizona)
    FIGURE 1. The LSST mirror has been cast and is ready for grinding and polishing. The outer 5- to 8.4-m-diameter portion will serve as the primary mirror; the inner 5-m-diameter portion will be ground to a steeper curvature and will become the telescope’s tertiary mirror.
    Research

    TECHNOLOGY REVIEW 2008: Photonic feats

    John Wallace
    Dec. 1, 2008
    It was a year in which metamaterials began to take shape as optics, 80-attosecond pulses probed intra-atom electronic properties, optical interconnects benefited the digital revolution...
    (Courtesy of E. F. Schubert, www.lightemittingdiodes.org)
    FIGURE 1. The three binary compounds are shown in this plot of bandgap energy and wavelength versus lattice spacing at room temperature for the GaInAlN family of semiconductors.
    Lasers & Sources

    PHOTONIC FRONTIERS: SEMICONDUCTOR UV LASERS: Materials are a tough challenge for ultraviolet diode lasers

    Jeff Hecht
    Dec. 1, 2008
    Aluminum gallium nitride can emit light at wavelengths close to 200 nm, but developers need another breakthrough in materials before they can push semiconductor diode lasers into...
    Research

    IR FIBERS: Silicon core is highly crystalline

    John Wallace
    Dec. 1, 2008
    Scientists at Clemson University (Clemson, SC) have figured out how to fabricate a silicon (Si)-core, glass-clad optical fiber using a conventional fiber-draw process.
    FIGURE 1. The combination of a quadruple bandpass filter with a CMYG color CCD modifies the sensitivity of the color pixels. Each pixel has a different level of sensitivity to each of the four narrow spectral bands.
    Detectors & Imaging

    BIOSPECTROSCOPY: High-resolution sensors capture application defined spectral bands in real time

    Dec. 1, 2008
    A new and highly potent technique allows concurrent capture of application-defined spectral bands using standard color CCD cameras.
    (Courtesy of University of St. Andrews)
    An optical Airy beam (shown in white, illuminating from below a sample) exerts an optical gradient force on dielectric particles in suspension. In a “snowblowing” effect, the outer lobes of the Airy beam sweep a homogeneous mixture of particles toward the main spot in the beam (left), or toward the lower-left region of the sample area. If the beam is rotated by 180º (right), the particles are then swept toward the upper-right region of the sample area.
    Research

    OPTICAL MANIPULATION: Airy light ‘throws a curve ball’

    Gail Overton
    Dec. 1, 2008
    Named after the famous British astronomer Sir George Airy, the Airy beam does not diffract or spread and can actually bend or curve as it propagates; in 2007, Airy light beams...
    (Courtesy of Prism Solar Technologies)
    FIGURE 1. Holographic film (left), when used in a planar concentrator, collects light in areas not populated with PV cells (above). A mono-facial module design uses 50% less silicon than a conventional panel (right).
    Optics

    OPTICS FOR SOLAR ENERGY: Holographic planar concentrator increases solar-panel efficiency

    Mike Zecchino
    Dec. 1, 2008
    In a holographic planar concentrator, holographic film diffracts usable frequencies of sunlight, and guides that energy toward strips of solar cells, resulting in a solar module...
    (Courtesy of Boston University)
    Two-dimensional (x-y) QOCT sections of an onion-skin sample were taken at different axial (z) depths.
    Optics

    QUANTUM PHOTONICS: Nonclassical OCT images biological sample

    Barbara Gefvert
    Dec. 1, 2008
    Quantum optical coherence tomography (OCT) has, for the first time, been shown to be a viable biological imaging technique, says M. Boshra Nasr, a postdoctoral researcher in the...
    (Courtesy of Lawrence Livermore National Laboratory)
    The Laser Inertial-Confinement Fusion-Fission Energy (LIFE) approach will be much more compact than The National Ignition Facility (NIF) laser source. A successful LIFE engine could efficiently consume dangerous stockpiles of spent nuclear fuel, natural and depleted uranium, and weapons-grade plutonium, and produce carbon-free energy into the 21st century and beyond.
    Research

    LASER FUSION-FISSION: NIF is precursor to LIFE project

    Gail Overton
    Dec. 1, 2008
    The goal of the U.S. National Ignition Facility at Lawrence Livermore National Laboratory, due for completion in March 2009, the Laser MegaJoule , and the European High-Power ...
    Th New Pla 01
    Optics

    New planar metamaterials structures may act as chemical-agent detectors

    Dec. 1, 2008
    In addition to their starring role in negative-refractive-index materials and cloaking devices, metamaterials may play a new part in detectors of biological and chemical agents...
    (Courtesy of IMRA America)
    FIGURE 1. Scalable femtosecond lasers used at high scan rates perform well for cutting wafers, but results vary depending on scan speed. A SEM image of a wafer cut at 4 m/s scan speed (left) shows cleaner singulation than at 80 mm/s scan speed (right).
    Fiber Optics

    ULTRAFAST FIBER LASERS: Femtosecond fiber laser enables reliable wafer-level processing

    Dec. 1, 2008
    Wafers singulated by a high-repetition-rate femtosecond fiber laser at high scan speeds show significantly higher breakage strength than those processed by a nanosecond laser....
    FIGURE 1. The typical photon-detection efficiency for a DAPD design has a nearly flat spectral response between 300 and 700 nm. The dashed red line represents measured photon-detection efficiency (sensitivity). Oscillations in efficiency are caused by optical interference due to lack of an antireflective coating. The solid blue line is the approximation of the experimental curve, fit through measured peak points. The dashed yellow curve, based on simulations, corresponds to the more accurate elimination of optical losses and represents the spectral response of the photodetector with an ideal antireflection coating.
    Detectors & Imaging

    SINGLE-PHOTON DETECTORS: Discrete amplification dramatically improves single-photon detection

    Dec. 1, 2008
    A new type of photodetector overcomes the limitations of avalanche photodiode technology by offering amplitude and event detection, wide dynamic range, and flat spectral response...