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  • Volume 49, Issue 03

    More content from Volume 49, Issue 03

    (Courtesy of Terrones Lab, Penn State University)
    Monolayered triangular structures of tungsten disulfide exhibit photoluminescence at their edges. Inset is an artist’s rendition of the molecular structure of the triangles.
    Pennsylvania State University (Penn State) researchers have succeeded in fabricating single- and few-layer metal dichalcogenide two-dimensional (2D) triangular microplatelets ...
    March 11, 2013
    Courtesy of J. Sun and M. Watts, MIT
    Light entering an array of nanophotonic antennas is distributed through silicon waveguides to individual antenna elements (right). Couplers are designed to deliver the same power to all array elements, which direct most of the light upward.
    Using silicon fabrication technology, a team at the Massachusetts Institute of Technology (MIT) has taken a huge leap forward in the development of phased arrays of optical nanoantennas...
    March 11, 2013
    Bio-inspired optical fibers change color when stretched
    Inspired by nature, materials scientists at Harvard University and the University of Exeter have invented a new fiber that changes color when stretched.
    March 8, 2013
    Researchers at the University of Vienna in Austria have created what they call a universal matter-wave closed-path interferometer; the gratings that steer the beams of matter ...
    March 8, 2013
    Two École Polytechnique Fédérale de Lausanne (EPFL) scientists have developed a device that can create three-dimensional (3D) images of living cells and track their reaction to...
    March 7, 2013
    Fed by an optical waveguide, an optical nanoantenna can be used to emit infrared (IR) or visible light in a highly directional manner (just as a radio antenna does for radio waves...
    March 7, 2013
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    Researchers from Johns Hopkins University and the US Army Research Laboratory have developed a methodology to trigger the folding process for microstructures from afar using low...
    March 6, 2013
    Researchers at the University of Sydney in Australia and Université Paris Sud in France have recently accomplished self-assembly of silica microwire waveguides on hydrophilic ...
    March 6, 2013
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    Researchers at the University of Eastern Finland, Aalto University, and the Royal Institute of Technology have created an achromatic Young's interferometer by inserting an achromatic...
    March 5, 2013
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    Scientists in France and Singapore have both analytically and numerically modeled types of hybrid electromagnetic modes that they call plasphonic modes.
    March 5, 2013
    FIGURE 1. A THz-Raman system that works with any single-stage spectrometer (inset) extends traditional Raman into the terahertz spectroscopy regime, with no upper limit to spectral range and simultaneous capture of anti-Stokes Raman shifts.
    Ultranarrowband volume holographic grating (VHG)-based notch filters can extend the range of Raman spectroscopy into the terahertz regime using a single-stage spectrometer, yielding...
    March 1, 2013
    Conard 720
    Many great sources of information exist for keeping track of developments in photonics technologies and products.
    March 1, 2013
    FIGURE 1. Typical screw-in alignment technology for a camera module assembly can lead to poor image focus (a), while alignment in five or six degrees of freedom (DOF) produces optimized on-axis and off-axis focus (b).
    Software algorithms gather feedback from an active lens-to-sensor alignment process to adapt and improve camera performance for more efficient cycle times.
    March 1, 2013
    FIGURE 1. The strength distribution for samples of the prototype fiber, which has a 100 μm glass diameter and an enhanced coating, was measured at 35°C and 90% relative humidity using a two-point-bend configuration (a). Theoretical lifetime predictions are shown (b) for a fiber with the smaller 100 μm glass diameter (blue) and a fiber with the conventional 125 μm diameter (red). For a 3 mm bend diameter, the lifetime for the 100-μm-diameter fiber is four orders of magnitude greater than for the 125-μm-diameter fiber. Experimental direct lifetime measurements (blue points) for the 100-μm-diameter fiber match up well with theory.
    A novel fiber design with an optimized smaller diameter can survive bending and pinching, allowing consumers to create high-speed home optical networks.
    March 1, 2013
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    Properly optimized volume Bragg grating (VBG)-based upper-state laser diode pumping leads to performance and power improvements for diode-pumped solid-state (DPSS) lasers.
    March 1, 2013
    FIGURE 1. In a FINCH microscope configuration for holographic imaging, a fluorescent slide is positioned on a microscope stage and illuminated by standard epifluorescence methods. The fluorescence emission is passed through an input polarizer aligned at some angle to the polarization-sensitive axis of the SLM; the emission beam reflects off the SLM containing the appropriate diffractive lens patterns and then through an output polarizer before reaching the CCD camera.
    A method for creating digital holograms of incoherent objects, dubbed Fresnel incoherent correlation holography (FINCH), creates holograms by a single-channel, on-axis, incoherent...
    March 1, 2013
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    As backscatter x-ray full-body scanner systems lose ground in favor of the "nonionizing" radiation from terahertz and millimeter-wave scanning and imaging systems, safety questions...
    March 1, 2013
    FIGURE 1. Approximate power and beam quality requirements for selected materials-working processes. Details vary with material parameters. Generally larger beams are used in applications that do not require high beam quality, such as hardening and cladding. Applications that require high intensity, such as metal cutting, typically require small spots. BPP is a measure of beam quality.
    Direct laser diode output, delivered in a line beam or through an optical fiber, is attractive for applications ranging from heat treating and cladding to welding. But the beam...
    March 1, 2013