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  • Volume 44, Issue 9

    • Volume 44, Issue 9

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    Research

    Reading LIPS: the science of microstructuring using femtosecond lasers evolves

    Sept. 1, 2008
    Researchers at Huai Hai Institute of Technology (Lianyungang City, China) have probed the effect of femtosecond laser fluence and pulse number on the formation of microstructures...
    Optics

    Silver-nanoprism solution functions as an optical limiter

    Sept. 1, 2008
    Optical limiters are nonlinear materials that exhibit a drop in transmittance as the energy of incident laser pulses increases, usually above a certain threshold.
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    Optics

    High-efficiency flat-screen pixel uses tiny telescopic optics

    Sept. 1, 2008
    The standard liquid-crystal display transmits only 5% to 10% of its backlight—a large waste of energy and, for mobile devices, battery life.
    Lasers & Sources

    Metallized silicon substrates reduce LED costs

    Sept. 1, 2008
    Commercial gallium nitride (GaN)-based light-emitting diodes (LEDs) are typically fabricated on expensive sapphire or silicon carbide substrates that are also difficult to dice...
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    Test & Measurement

    Lidar maps dinosaur trackways

    Sept. 1, 2008
    Paleontologists now have a new tool to perform 3-D interpretations of complex sets of dinosaur trackways: light detection and ranging (lidar).

    More content from Volume 44, Issue 9

    FIGURE 1. Bend radii and loss compared for three types of fibers designed specifically for fiber drops. G652 is standard single-mode fiber; other types were designed with reduced bend losses, specified for a given number of turns around a mandrel of the specified size.
    Software

    PHOTONIC FRONTIERS: FIBER TO HOME - Fiber to the home takes aim at a ‘100-megabit nation’

    Jeff Hecht
    Sept. 1, 2008
    Technology innovation is being driven by the goal of scaling up FTTH to 100 megabits per second throughout the U.S. by 2015.
    (Courtesy of Harvard University and Hamamatsu Photonics)
    The grooves on the face of a metal-coated quantum-cascade laser (top) act effectively as an antenna to concentrate light exiting a slit into a small solid angle. The two-dimensional far-field intensity distribution was measured from above the QCL facet (bottom). The slight curvature of the output is an edge effect.
    Lasers & Sources

    PLASMONICS: Surface-plasmon collimation narrows the beam of semiconductor lasers

    Valerie Coffey-Rosich
    Sept. 1, 2008
    Unlike gas and solid-state lasers that emit in a characteristically narrow beam, edge-emitting semiconductor lasers have a wide beam divergence, requiring bulky optics and meticulous...
    (Courtesy of Rice University)
    FIGURE 1. In a terahertz single-pixel camera experimental setup (top; schematic at bottom), an opaque object with a transmissive hole shaped as the letter “R” is imaged through a mask consisting of a random pattern of opaque pixels.
    Detectors & Imaging

    TERAHERTZ IMAGING: Single-pixel terahertz camera speeds measurement

    Sept. 1, 2008
    A terahertz camera with a one-pixel detector can be the solution to high-speed imaging in the terahertz region for detecting concealed weapons at airports, locating defects in...
    (Courtesy of ANU)
    The quantity of remaining atoms in the laser mode (red) of an atom-laser BEC (yellow) varies depending on whether or not the system is being pumped. The initial quantity (a) increases with pumping and no outcoupling (b), stays the same with pumping and outcoupling (c), and decreases with outcoupling but no pumping (d). Independence of pumping and outcoupling mechanisms indicates that atom replenishment is functioning properly. The curves are calculated from a rate-equation model, and error bars (red) represent the standard deviation of the mean calculated from repeated independent measurements.
    Research

    ATOM LASERS: Atom source for condensate is quantum leap for atom optics

    Hassaun A. Jones-Bey
    Sept. 1, 2008
    Recently reported research results from Australian National University (ANU; Canberra, Australia) appear to pave the way for development of continuous-wave (CW) free-space atom...
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    Research

    PHOTONIC-CRYSTAL FIBERS: Hollow-core PCFs enable high nonlinearity at low light levels

    Sept. 1, 2008
    The development of nonlinear and quantum optics applications based on gas-phase materials has been impeded by the lack of a suitable technology for creating devices that guide...
    FIGURE 1. Optimized for high-volume applications in fluid delivery, endoscopy, and embedded zoom and autofocus functions in cameras, this patented mechanism is a motor and stage in one high-speed, ultraminiature package.
    Positioning, Support & Accessories

    NANOPOSITIONING: Long-travel piezomotors ‘reboot’ the motion-control toolbox

    Scott Jordan
    Sept. 1, 2008
    Novel piezoelectric technology provides essentially unlimited travel distances, along with high axial force, exceptional speeds, compactness, and stable position-hold without ...
    (Courtesy of University of Hertfordshire)
    The scattering pattern of individual ice crystals (left) can be used to accurately identify the size and shape of a micron-size column and hexagonal platelet of ice (right). Such microscopic data, which was previously unattainable, can aid in understanding how clouds affect Earth’s climate.
    Research

    ATMOSPHERIC STUDIES: Ice crystal shapes are assessed in the Earth’s atmosphere

    Valerie Coffey-Rosich
    Sept. 1, 2008
    Atmospheric scientists have created an optical-scattering instrument designed to capture high-resolution spatial light-scattering patterns of ice crystals like those found in ...
    Research

    Light-tugged molecules reveal molecular forces

    Sept. 1, 2008
    To better understand how interactions between molecules within a cell regulate such activities as the properties of the cytoskeleton as well as critical division and growth processes...
    (Courtesy of Massachusetts Institute of Technology)
    A grating is fabricated using four 200-nm-period grating levels in a unique interference-lithography process (left). The fourth exposure produces a 50-nm-period grating with feature sizes as small as 25 nm (right).
    Optics

    LITHOGRAPHY: Interference lithography creates 50-nm-period gratings

    Gail Overton
    Sept. 1, 2008
    Although still not capable of producing the complex, nonperiodic structures necessary for most integrated-circuit (IC) designs, interference lithography has been used to successfully...
    FIGURE 1. DNA possesses some interesting optical and electrical properties, and is being explored as a natural material for synthesis into biopolymer thin films that can be used in a variety of optoelectronic devices.
    Research

    OPTOELECTRONIC APPLICATIONS: DNA PHOTONICS - Next-generation optoelectronics leverage DNA biopolymers

    Gail Overton
    Sept. 1, 2008
    Made mainstream by its role in human-genome mapping, genetic-trait analysis, and forensics, deoxyribonucleic acid is also playing a role as a biopolymer for the creation of novel...
    FIGURE 1. A white-light continuum source is formed by sending 775 nm pulsed laser light through Krypton gas, creating energy for use in nonlinear experiments at any wavelength from 400 to 800 nm.
    Optics

    NONLINEAR OPTICS: The dream of a turnkey nonlinear spectrophotometer gets closer to reality

    Sept. 1, 2008
    Where linear spectrophotometers leave off, high-power ultrafast lasers and novel white-light continua are enabling novel nonlinear Z-scan devices that measure two-photon absorption...
    Very slightly steering one of two ultrafast pump beams impinging on a nonlinear optical device greatly steers the resulting terahertz beam.
    Research

    OPTICAL COMMUNICATIONS: Difference-frequency generation steers terahertz beams quickly

    John Wallace
    Sept. 1, 2008
    Two researchers at RIKEN (Sendai, Japan) have come up with a way of quickly and easily steering a beam of terahertz radiation over a wide angular range (potentially ±90°).
    Research

    Hybrid waveguide tightly confines light, has long-range transmission

    Sept. 1, 2008
    A hybrid optical-plasmonic waveguide developed by researchers at the University of California, Berkeley, confines 1550 nm light to dimensions far below a wavelength in two dimensions...
    Optics

    Bioactive silk protein makes optical devices edible

    Sept. 1, 2008
    Silk-based biomaterials have unique biophysical features that can be exploited to create optical sensors that could host “living” blood or pH indicators, and would biologically...
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    Positioning, Support & Accessories

    ORGANIC SEMICONDUCTOR SOURCES: Hybrid OLEDs combine vapor deposition with solution processing

    Sept. 1, 2008
    Current organic-light-emitting-diode (OLED) device performance meets or exceeds the requirements for display applications.