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  • Volume 44, Issue 3

    • Volume 44, Issue 3

    Home

    SCIENCE & TECHNOLOGY EDUCATION: Biophotonics graduate student reaches out to young students

    March 6, 2008
    Through a grant from the Optical Society of America Foundation, Ruby Raheem of the University of Edinburgh recently traveled to Ghana, Dubai, and India to give optics demonstrations...
    Research

    Gamma rays challenge e-beams for writing waveguides

    March 1, 2008
    Researchers at National Taiwan University (Taipei, Taiwan) and National Tsing-Hua University (Hsinchu, Taiwan) are showing that gamma-ray irradiation may be superior to electron...
    Lasers & Sources

    Tunable 2 µm disk laser achieves 5 W

    March 1, 2008
    Mid-infrared lasers for applications in pollution monitoring, remote sensing and ranging, free-space optical communications, and medical diagnosis require a high-brightness, compact...
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    Research

    3-D holographic display is updatable and rewritable

    March 1, 2008
    Researchers from the University of Arizona, in conjunction with Nitto Denko Technical Corporation (Oceanside, CA), have created a holographic three-dimensional (3-D) display that...
    Research

    Laser Focus World seeks a senior technical editor

    March 1, 2008
    If you are interested in advanced technologies and have a background in science journalism with a science or engineering degree we would like to hear from you.

    More content from Volume 44, Issue 3

    (Courtesy of Kopin)
    FIGURE 1. A schematic cross-sectional view shows a full-color Kopin CyberDisplay liquid-crystal display (LCD) with color filters. The light transmission through each color dot is independently controlled by the voltage applied to each pixel electrode, resulting in a wide full-color gamut.
    Detectors & Imaging

    HOMELAND-SECURITY IMAGING: Microdisplays advance military imaging

    March 1, 2008
    Transmissive liquid-crystal technology based on single-crystal silicon backplanes enables ultralow power consumption, wide operating-temperature range, and “instant-on” performance...
    (Courtesy of R. Noak/Max Planck Institute)
    FIGURE 1. The basic structure of 3-D metamaterials is illustrated in this artist rendering.
    Research

    PHOTONIC METAMATERIALS: Researchers create 3-D photonic metamaterials

    Sally Cole Johnson
    March 1, 2008
    Moving a step closer to optical cloaking, researchers at the University of Stuttgart (Stuttgart, Germany) recently created a stacked split-ring metamaterial for the optical wavelength...
    (Courtesy of The Spaceward Foundation)
    FIGURE 1. An artist’s rendering illustrates the concept of the space elevator, a platform powered by a ground-based laser-diode unit that climbs into space from Earth on a ribbon or tether.
    Lasers & Sources

    HIGH-POWER DIODE LASERS: High-power diode lasers boost power-beaming competition

    March 1, 2008
    Improved efficiency of diode lasers and the growing photovoltaic market have accelerated interest in power beaming (wireless power transfer). The NASA-sponsored Space Elevator...
    (Courtesy Stanford University)
    A scanning-electron micrograph shows a silicon island surrounded by coiled silicon wires (top). When the wires are uncoiled and attached to other silicon islands, the flexible array (bottom) can be used for large-area silicon-based applications including lower-cost solar cells and distributed sensor arrays.
    Optics

    SILICON PHOTONICS: Silicon ‘expands’ to meet large-area applications

    Gail Overton
    March 1, 2008
    When we think about silicon photonics, we often picture a uniform, monolithic wafer of material.
    (Courtesy of Odae Kwon, POSTECH)
    A blue photonic-quantum-ring laser showcases 3-D whispering-cave-mode emission with ultralow threshold current less than that of VCSELs or LEDs.
    Research

    QUANTUM-RING LASERS: Whispering-cave-mode lasers emit in blue-violet

    Valerie Coffey-Rosich
    March 1, 2008
    Lord Rayleigh wrote about the two-dimensional whispering gallery mode (WGM) in 1910 after a visit to the dome of St. Paul’s cathedral in London.
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    Research

    Remote cathode paves way for electrically pumped organic laser

    March 1, 2008
    The path toward creating an electrically pumped organic laser is hindered by the fact that metallic contacts quickly absorb light in organic light-emitting diodes (OLEDs) and ...
    FIGURE 1. The impact of adaptive optics on laser spot quality is evident from these images comparing corrected and uncorrected laser output. The Strehl ratio (the ratio between the actual spot intensity and the theoretical maximum intensity), increases from less than 0.1 without correction to more than 0.9 when adaptive-optics correction is applied.
    Optics

    ADAPTIVE OPTICS: Optical fuse protects intracavity laser components

    March 1, 2008
    An adaptive-optics phase-correction mechanism combined with a specially designed filter can prevent catastrophic damage to critical optical components in a high-intensity laser...
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    Lasers & Sources

    Lasers turn pure aluminum … ‘gold’

    March 1, 2008
    The ultimate goal of the Old World alchemist was to turn inexpensive metals into gold.
    (Courtesy of Boris Zhdanov)
    A hydrocarbon-free potassium alkali laser with buffer gas pressure below 1 atmosphere emits at 770 nm and shows no carbon contamination at operating temperatures up 150ºC (top). A system containing ethane shows contamination at 120ºC (bottom).
    Research

    ALKALI LASERS: Demonstrations show advance of alkali lasers

    March 1, 2008
    Progress is being made in the development of diode-pumped alkali-vapor lasers, according to a paper presented by Boris Zhdanov, research professor in the Laser and Optics Research...
    FIGURE 1. An optical cell-density probe provides real-time, in situ process data, measuring the optical loss across a known distance (OPL) to give a measure of the suspended-particle density.
    Test & Measurement

    BIOPROCESS MONITORING: Photonics takes a new look at bioprocesses

    March 1, 2008
    Optically based monitoring of bioprocess reactors enables real-time, noninvasive interrogation of the bioprocess state, bringing the promise of significant improvements in process...
    FIGURE 1. The measured threshold for corneal damage from nanosecond pulses in J/cm2 (blue bars) tracks the 95% absorption depth in the cornea (green dotted line), which is close to that of water (yellow line). Because the data show absorption depth, the low points in the curve correspond to peaks of attenuation where light is absorbed very efficiently. The dashed black line is a linear fit of the data, which safety specialists propose as a tool to calculate maximum permissible exposures.
    Research

    PHOTONIC FRONTIERS: EYE-SAFE LASERS - Retina-safe wavelengths benefit open-air applications

    Jeff Hecht
    March 1, 2008
    Shifting to wavelengths not transmitted to the retina relaxes eye-safety requirements for applications that require beam transmission through open air, but corneal safety remains...
    (Courtesy of Nature magazine)
    A short-time Fourier transform shows the time-wavelength profile of an optical rogue wave, generated within a nonlinear optical fiber from a gradual seed pulse with weak noise perturbations. The broadband wave has steep slopes in the time domain compared with typical events just like rogue waves seen on the open ocean, which have been described as “walls of water.”
    Research

    OPTICAL THEORY: Scientists capture optical ‘rogue waves’

    Gail Overton
    March 1, 2008
    Once thought to be mythical, giant waves on the open ocean that could swallow entire ships before vanishing without a trace were finally recorded for the first time at the Draupner...
    Positioning, Support & Accessories

    3-D stability analysis predicts optofluidic interactions in waveguides

    March 1, 2008
    Building on previous work in optofluidics using polymer waveguides, engineers from Cornell University (Ithaca, NY) have devised a comprehensive model for particle-trapping stability...
    Optics

    Photoaligned liquid-crystal polymers create vortex retarders

    March 1, 2008
    Optical designers require radially and azimuthally polarized beams to improve performance of systems like confocal microscopes and lithography systems.
    (Courtesy of IBM)
    FIGURE 1. IBM’s new silicon Mach-Zehnder optical modulator converts a digital electrical signal carried on a wire into a series of light pulses carried on a silicon nanophotonic waveguide. The waveguides are made of tiny silicon strips (purple) in a silicon-on-insulator wafer (inset).
    Optics

    OPTOELECTRONIC APPLICATIONS: NANOPHOTONICS - Silicon photonics sets the stage for optical datacom

    Kathy Kincade
    March 1, 2008
    Nanoscale techniques are yielding chip-level modulators, transceivers, VOAs, and even lasers—all made from silicon.