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  • Volume 44, Issue 7

    • Volume 44, Issue 7

    Lasers & Sources

    Extremely broadband quantum-dot LEDs realized via rapid thermal annealing

    July 1, 2008
    Researchers at the University of Sheffield (Sheffield, England) and the Chinese Academy of Sciences (Beijing) have reported the first demonstration of ultrabroadband superluminescent...
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    Research

    First optical pacemaker uses femtosecond pulses

    July 1, 2008
    Once the job of electrons, stimulating heart cells is now being done by photons.
    Positioning, Support & Accessories

    Light-driven brake stops molecular machines

    July 1, 2008
    Molecular machines (either synthetic or biological) are defined as molecules or groups of molecules that perform mechanical-like movements in response to certain stimuli (light...
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    Research

    Photonic beetle is nature’s answer to optical computers

    July 1, 2008
    The scales of an inch-long beetle from Brazil possess properties that scientists have not been able to fabricate synthetically.
    Software

    OpenFilters optical-filter-design software is released under open-source license

    July 1, 2008
    The boom in popularity of the Linux operating system in the past few years is resulting in, for example, the design of very low-cost laptop computers specifically around Linux...

    More content from Volume 44, Issue 7

    (Courtesy University of Tokyo)
    A near-field photochemical photodissociation process uses a 532 nm continuous-wave laser to reduce the 2.36 Å surface roughness of silica obtained with conventional chemical-mechanical polishing techniques (left) to only 1.37 Å (right).
    Research

    NANOPHOTONICS: Near-field polishing yields ultraflat silica surface

    Gail Overton
    July 1, 2008
    Conventional chemical-mechanical polishing (CMP) methods are typically used to obtain surfaces figured to sub-100-nm tolerances on optical and semiconductor materials for specialized...
    FIGURE 1. An experimental one-dimensional interferogram from a FTIR-FPA is symmetrized by duplicating and flipping it about the zero-path-length point on the plot. A Fourier transform is then taken of this data to obtain a spectral curve.
    Test & Measurement

    FOURIER-TRANSFORM SPECTROSCOPY: Interferometer simplifies FTIR spectrometer

    John Wallace
    July 1, 2008
    If a handheld spectrometer could be created that operated without the need for a spectral-scanning mechanism, its resulting simplicity and low cost would greatly expand its practical...
    (Courtesy of Fraunhofer IPMS)
    FIGURE 1. Scanning-electron-micrograph images show a scanning grating chip; the size of the grating area is typically limited to 3 × 3 mm² because of process and mechanical limitations. The grating moves with a speed between 130 to 150 Hz.
    Detectors & Imaging

    Spectrometers: MOEMS scanning grating chips reveal spectral images

    July 1, 2008
    Hyperspectral imaging is used for a broad variety of applications ranging from the harvesting of agricultural goods to waste selection in recycling processes.
    Research

    OPTICS INDUSTRY REPORT

    July 1, 2008
    SUSS MicroTec (Munich, Germany), supplier of solutions for the microelectromechanical systems, advanced packaging, and nanotechnology markets, entered into a license agreement...
    (Courtesy of Yokohama National University and CREST)
    Four of the airholes in a hexagonal nanolattice in a GaInAsP single-quantum-well wafer are shifted -- two laterally by 60 nm (Sx) and two longitudinally by 120 nm (Sy). The result is a nanolaser cavity that achieves continuous-wave lasing in the 1550 nm region when pumped by light at 980 nm. As the refractive index of the surrounding gas or fluid changes, the wavelength of the nanolaser changes, allowing monitoring of the index.
    Research

    OPTOFLUIDICS: Nanolaser becomes a refractive-index sensor

    John Wallace
    July 1, 2008
    Measuring the change in refractive index of a liquid induced by the entry of a foreign substance is one way to determine whether the liquid has become contaminated.
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    Detectors & Imaging

    CMOS Detectors: Scientific monolithic CMOS imagers come of age

    July 1, 2008
    Imagers based on monolithic complementary metal-oxide semiconductors (CMOS) were first introduced as a competitor to charge-coupled-device (CCD) detectors more than a dozen years...
    (Courtesy of the Foundation for Research and Technology-Hellas)
    A scanning-electron micrograph of the actual device.
    Research

    LIGHT-EMITTING DIODES: Polariton LED is electrically pumped

    Gail Overton
    July 1, 2008
    Researchers at the University of Crete and the Foundation for Research and Technology-Hellas (both in Heraklion, Crete, Greece) have created an electrically pumped polariton light...
    (Courtesy of Fianium and Tampere University of Technology)
    FIGURE 1. A fiber laser can be used for pulsed laser deposition to fabricate smooth zirconium oxide films on silicon. The picosecond pulses allow deposition of amorphous films at room temperature and the high repetition rate enables the upscaling of the growth rate while maintaining the high quality of the deposited films. Growth rate is comparable to other pulsed vapor deposition methods and is in the range of a few nanometers per second.
    Fiber Optics

    OPTOELECTRONIC APPLICATIONS: MICROPROCESSING - Ultrafast fiber lasers forge new microprocessing frontiers

    Gail Overton
    July 1, 2008
    Although solid-state lasers will continue to play a role in microprocessing, the high repetition rate and high peak power of today’s ultrafast fiber lasers are getting noticed...
    Steve Anderson, Laser Focus World editor-in-chief and associate publisher (center), presents the 2008 PhAST/Laser Focus World Innovation Award to Andrew Masters (right), a director of marketing at Coherent, for Coherent’s OPSL-577-3, an optically pumped semiconductor laser at 577 nm targeted for the treatment of age-related macular degeneration, as David Huff, vice president of marketing and business development for the Optoelectronics Industry Development Association, looks on. To view video interviews with award recipients, see www.laserfocusworld.com/resourcecenter/video.html.
    Research

    CLEO/QELS & PhAST 2008: Research reigns supreme at annual conference

    Valerie Coffey-Rosich
    July 1, 2008
    Despite mixed reviews from exhibitors on the show floor at the Conference on Lasers and Electro-Optics, Quantum Electronics and Laser Science Conference, and the Photonic Applications...
    A lasing spaser consists of a thin slab of a dielectric gain medium (center) underneath an array of asymmetric split-ring resonators. In a single translation cell of the array, asymmetric currents of plasmonic oscillations in phase with the other cells produce emission of spatially and temporally coherent light that propagates in a direction normal to the array. The arc angles of the nanowire segments, β1 and β2, determine the Q-factor and coupling intensity.
    Research

    PLASMONICS: Lasing spaser creates coherent radiation

    Valerie Coffey-Rosich
    July 1, 2008
    A new type of nanoscale optical device called a lasing spaser combines metamaterials and spasers to create a versatile planar source of coherent radiation.
    FIGURE 1. Several objective design forms can be used in IC inspection applications: (from left) all-fused-silica design is ideal for monochromatic applications; all-refractive design with CaF2 positive lenses and fused-silica negative lenses gives moderate bandwidth; a catadioptric design form with off-axis field can extend bandwidth; and an obscured, essentially all-reflective design offers wide bandwidth, with a large monolith that has one refractive and two reflective surfaces.
    Optics

    Optical Imaging: Inspection applications push imaging lenses into the deep

    July 1, 2008
    Semiconductor inspection and yield-enhancing tools are pushing design of imaging objectives into the deep-ultraviolet part of the spectrum and high numerical apertures.
    (Courtesy of the Capasso Lab, Harvard School of Engineering and Applied Sciences)
    One of the lasers in a bar with 10 terahertz laser sources is connected to the contact pad (left) by two thin gold wires. A 2-mm-diameter silicon hyperhemispherical lens is attached to the facet of the device to collimate the terahertz output. The emission frequency is 5 THz, corresponding to a wavelength of 60 µm.
    Lasers & Sources

    TERAHERTZ SOURCES: QCLs make a difference in room-temperature terahertz

    D. Jason Palmer
    July 1, 2008
    The terahertz region has long been described as the last frontier in the electromagnetic spectrum, with promises of endless applications in imaging, sensing, and security.
    FIGURE 1. A high-resolution spectrometer used in combination with a telescope measures changes in the wavelength of light coming from a star over the course of days, months, and years. The change in color is caused by the Doppler shift of the light, resulting from the star orbiting a common center of mass with a companion planet (referred to as stellar wobble). Because of the large size of the star in comparison to the planet, the center of mass of a planet-star pair is often located within the star.
    Research

    Ultrafast lasers: Frequency combs refine Doppler search for distant planets

    July 1, 2008
    Detecting the exceedingly small Doppler shifts from parent stars and orbiting planets in other solar systems will require extremely sensitive instruments.
    FIGURE 1. Three types of coherent beam combination include a common resonator keeps multiple laser elements in phase (top); an evanescent-wave coupling between closely spaced laser elements keeps their output in phase (center); and an active feedback loop, with wavefront sensors detecting the phase of each laser element fed by a master oscillator, then modulating the phase of each element (bottom).
    Optics

    Photonic Frontiers: beam combining - Combining beams can boost total power

    Jeff Hecht
    July 1, 2008
    Efforts to scale the output power of a single-output laser inevitably run into limits.
    (Courtesy of University of Padua)
    In the satellite single-photon link, a fraction of the beam in the uplink path irradiates the satellite. The corner cubes on the satellite retroreflect a small portion of the photons in the laser pulse back to the Earth (in green).
    Research

    QUANTUM COMMUNICATIONS: Single-photon exchange advances Earth-to-space quantum link

    Valerie Coffey-Rosich
    July 1, 2008
    A quantum communications link in space is one step closer after Italian researchers successfully detected a single photon sent from Earth to a low-Earth-orbit satellite and back...