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    • Volume 47, Issue 6

    More content from Volume 47, Issue 6

    Time was when the buying and reading of a new book was quite simple. If you read a promising review of a recently published book, a quick phone call to your local bookseller would...
    June 1, 2011
    A magnetic field creates transitions between Zeeman sublevels in a 229Th nucleus, some of which can lead to a vacuum-ultraviolet nuclear laser—a precursor to a gamma-ray laser (Jπ = 5/2 is the ground state; Jπ = 3/2 is the first excited level; m are the sublevels).
    The "gamma-ray laser"—a much discussed but never before realized construct of nuclear physics—looks more plausible thanks to a new theoretical study.
    June 1, 2011
    Pennwell web 90 86
    We're almost halfway through 2011 and the imminent arrival of summer brings another set of solid financial reports from the public photonics companies.
    June 1, 2011
    (Courtesy of Awaiba GmbH)
    Through-silicon-via (TSV) technology enables low-cost CMOS cameras smaller than a match head.
    Building on earlier work that described breakthrough wafer-level-packaging developments related to miniature CMOS imagers with 1.7 µm pixel pitch, researchers at the Fraunhofer...
    June 1, 2011
    (Courtesy of the University of Michigan)
    The trajectory of electron motion (away from its nucleus at x = y = z = 0) in a dielectric material illuminated by an incident electric field strength of (a) 1 V/m is compared to illumination with a strength of (b) 108 V/m. For the low-intensity light field, the x and z axes differ by nine orders of magnitude and the electron moves along the electric field x. At a higher light intensity, motion shifts to z, the direction of light propagation, and is much larger than expected.
    Imagine converting the Sun's energy to electricity without the need for expensive semiconductor materials or the usual absorption-exciton-drift-current conversion steps. This ...
    June 1, 2011
    Cross-correlation traces show the difference in pulse delay for a 450 fs Stokes pulse passing through a 5 cm polymer waveguide (a). Delay time of the Stokes pulse is shown (b) for two values of the input Stokes bandwidth, 5 nm (blue) and 8 nm (purple).
    The generation of "slow light" (in which the group velocity of light in a material is slowed down substantially due to a specially tailored dispersion profile) is potentially ...
    June 1, 2011
    (Courtesy of OFS Denmark)
    The refractive index profile is shown for a germanium oxide depressed-cladding few-moded fiber (a) designed for optical-dispersion compensation in coherent communications networks. Its effective area and dispersion (b) exceed those for existing fiber designs.
    Scientists at OFS Denmark (Brøndby, Denmark) and OFS Labs (Somerset, NJ) have developed a dispersion-compensating optical fiber with a factor of 5.0 improvement in figure of merit...
    June 1, 2011
    FIGURE 1. In the fabrication process, the cleaved fiber end is first completely covered with a polymer (a). The polymer is then crosslinked hole by hole using a two-photon process (b). The fiber end is cleaned to prepare it for filling (c).
    The holes of a photonic-crystal fiber can be filled with optically nonlinear fluids in an arbitrary pattern, leading to versatile devices with properties such as soliton propagation...
    June 1, 2011
    (All images courtesy of Jeremy Baumberg)
    FIGURE 1. A core-shell (CS) system (a) based on polystyrene (PS)-polyethylacrylate (PEA) is used for polymeric opal production. The thin grafting polymer interlayer contains allyl methacrylate (ALMA). Batches of as-synthesised CS particles (b) may be extruded and processed into thin films (c), or long fibers of opaline quality (d). Crosslinked fibers may be knitted into fabrics (e), with a marked stretch-variable structural color effect (f).
    Polymer opal photonic-crystal fibers containing self-assembled submicron core-shell particles exhibit stretch-tunable color. These mechanically robust fibers can be produced in...
    June 1, 2011
    FIGURE 1. A long-wavelength VCSEL is based on a tunnel junction in a gain layer containing strained quantum wells of InAlGaAs/InP. AlGaAs/GaAs DBRs are bonded on top and bottom of the gain layer, with light emerging from the top.
    Widely used as low-power, high-efficiency laser sources, VCSELs are finding new applications as developers make the technology more versatile, increasing power, speed, and the...
    June 1, 2011
    FIGURE 1. Two-path interferometers include Michelson and Mach-Zehnder configurations. In this Michelson interferometer with single photodiode detection the sample and reference beams are split and recombined by the same beamsplitter (a). In the Mach-Zehnder interferometer with dual photodiode detection the sample and reference paths are recombined into a second optical combiner after passing through the reference delay and sample material (b).
    Use of autobalanced detectors to monitor the sample and reference beams of an interferometric system delivers high bandwidth with improved gain and reduced noise for applications...
    June 1, 2011
    (All images courtesy of InView Technology Corp.)
    FIGURE 1. A camera using a compressive-sensing (CS) architecture uses a digital-light processing (DLP) chip, a single-pixel detector, and reconstruction algorithms to construct an image. The incoming image is focused onto the DLP. For each successive diode reading, one-half of the image is reflected by the DLP to the diode. The processor reconstructs the image based on a series of diode readings and the associated mirror pattern for each reading.
    New detector materials such as quantum dots, carbon nanotubes, and graphene can significantly enhance the performance of infrared cameras within a rather short development cycle...
    June 1, 2011
    FIGURE 1. The manufacturing setups are shown for (a) a long-wavelength laser spike annealing (LSA) system and (b) a short-wavelength flash lamp annealing (FLA) system.
    The most recent advance in thermal processing equipment for semiconductor wafer manufacturing is millisecond annealing, which can be accomplished by two very different approaches...
    June 1, 2011
    Pennwell web 250 221
    The 2011 CLEO/Laser Focus World Innovation Awards program is designed to honor groundbreaking products in the field of photonics and laser science.
    June 1, 2011
    1106breaks Fig2a
    The secret to the shimmering brilliance of two beetles that shine naturally with silver and gold colors has been unlocked by researchers at Universidad de Costa Rica (San José...
    June 1, 2011
    FIGURE 1. The output pulse of a directly modulated laser diode shown in (a) can be divided into two parts: the initial overshoot region (c) and the primary region (d) by spectral filtering (b).
    Competing nonlinear processes have limited pulsed fiber lasers to modest peak powers, restricting application possibilities. But a new pulsed laser overcomes this barrier through...
    May 19, 2011