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  • Volume 47, Issue 10

    • Volume 47, Issue 10

    Content Dam Lfw Online Articles 2011 10 1110lfwnbf1web
    Optics

    3D interferometric microscopy reveals medical implant wear mechanisms

    Gail Overton
    Oct. 10, 2011
    Bruker Corp. says that 3D microscopy based on white-light interferometry can provide high-speed measurement with higher lateral resolution and better vertical measurement accuracy...
    Research

    IN MY VIEW: At last: A real reality show

    Jeffrey Bairstow
    Oct. 1, 2011
    To this writer, this year would appear to be the winter of his discontent made glorious summer by the publication of two fascinating but difficult books. They appear to shed some...
    1304qa Chang New
    Executive Forum

    Business Forum: What's stopping you from starting up?

    Milton Chang
    Oct. 1, 2011
    Do you believe age is a factor in starting a business?
    Probe (blue) and pump (red) pulses couple via a plasma wave, transferring energy from the pump to the probe pulse.
    Research

    NONLINEAR PROCESSES: Raman amplification sets sights on laser fusion

    D. Jason Palmer
    Oct. 1, 2011
    A pulse-amplification process designed for the highest-intensity short-pulse regime looks like it could lend its power to the effort toward laser fusion.
    Conard Holton2
    Research

    As fast as the speed of light

    Conard Holton
    Oct. 1, 2011
    The recent announcement from scientists at the particle accelerator at CERN that they have clocked neutrinos moving faster than the speed of light has generated considerable attention...

    More content from Volume 47, Issue 10

    (Courtesy of Bar-Ilan University)
    A noninvasive blood glucose, blood pressure, and heart-rate monitoring technique is based on the optical analysis of speckle patterns or “vibrations” reflected from human skin.
    Test & Measurement

    BIOPHOTONIC INSTRUMENTATION: Optical 'skin vibration' signature yields biological parameters

    Gail Overton
    Oct. 1, 2011
    Noninvasive, photonics-based blood glucose monitors for diabetes sufferers are being developed that use techniques such as optical coherence tomography (OCT) and Raman spectroscopy...
    In the Silex process, light at 10.8 µm from a CO2 laser is converted to a 16 µm wavelength and used to separate U-235 from U-238.
    Lasers & Sources

    LASER ISOTOPE SEPARATION: Laser uranium enrichment returns from the dead

    Jeff Hecht
    Oct. 1, 2011
    Satisfied with tests it completed last year on the Silex process for laser enrichment of uranium, GE Energy wants to build a massive nuclear-fuel plant based on the process.
    (Courtesy of E. Goulielmakis)
    A photonic system produces custom-shaped sub-femtosecond light transients used to probe the behavior of electrons within atoms. To create the transients, a supercontinuum is first divided into three channels (seen as blue, yellow, and red); beam parameters for each channel are manipulated before recombining the light (white).
    Research

    ATTOSECOND PHOTONICS: Sub-femtosecond sculpted light transients probe the atom

    John Wallace
    Oct. 1, 2011
    Attosecond (as) photonics is a rapidly developing tool to help scientists study the behavior of matter and energy at this extraordinarily short time scale.
    (Courtesy of X. Zhang)
    FIGURE 1. CdS nanowire laser produces surface plasmons that generate blue-green light from a subwavelength strip, where the nanowire rests on a silver slab coated with a thin layer of magnesium fluoride.
    Lasers & Sources

    PHOTONIC FRONTIERS: NOVEL LASERS: The incredible shrinking laser makes a big impact

    Jeff Hecht
    Oct. 1, 2011
    The cutting edge of laser technology keeps getting smaller. Optically pumped nanowire and plasmon lasers have reached subwavelength scales. Metal-clad semiconductor nanolasers...
    (Courtesy of the University of California–Berkeley)
    The trajectory of plasmonic Airy beams (PABs) can be manipulated by changing the angle of incidence of the light in the test setup. Experimental results show a PAB created with a 7º incident angle (a) and a 28º incident angle (b). The lower images are the corresponding numerical simulations (c) and (d), respectively. Scale bar is 5 µm.
    Research

    PLASMONICS: Airy beam controls the flow of surface plasmon polaritons

    Gail Overton
    Oct. 1, 2011
    Light can travel seemingly without diffraction in a curved arc in free space. Such peculiar optical beams are named "Airy beams" after English astronomer Sir George Biddell Airy...
    FIGURE 1. A schematic diagram depicts traditional pitch polishing of a sphere (a) and an asphere (b; exaggerated shape). The black arrows indicate the long strokes (>3 cm) made during polishing as the pitch lap is rubbed against the optic. In the VIBE compliant polishing process (c), the black arrow indicates the short strokes (1–2 mm) made during polishing as the conformal VIBE polishing lap is rubbed against the optic.
    Optics

    OPTICS MANUFACTURING: High frequency and random motion rapidly smoothes optical surfaces

    Oct. 1, 2011
    The VIBE process is a full-aperture, conformal polishing process that uses high-frequency, random motion to rapidly remove sub-surface damage and eliminate mid-spatial-frequency...
    A pump pulse changes the refractive index of a bR sample; as a result, the wavelength of a portion of a probe pulse selected by a grating changes at picosecond speed.
    Research

    BIOPHOTONICS: Optical protein switches at picosecond speeds

    John Wallace
    Oct. 1, 2011
    The development of all-optical data processing is getting a boost from European researchers who are pioneering the use of an optically active protein for ultrafast photonic switching...
    FIGURE 1. Typical spot welds on bare copper are large and irregular when using a 1064 nm Nd:YAG laser, but are much better controlled and uniform when using a 532 nm green Nd:YAG laser.
    Lasers & Sources

    PHOTONICS APPLIED: MATERIALS PROCESSING: Microwelding demands new laser tools

    Geoff Shannon, Ph.D.
    Oct. 1, 2011
    Welding small conductive parts is a unique challenge for welding technologies. Laser welding offers a great fit for this scale of joining; however, 1064 nm pulsed Nd:YAG technology...
    FIGURE 1. The outputs of two femtosecond fiber amplifiers are coherently combined using a fiber-coupled phase modulator with its error signal provided by a photodiode and associated electronics.
    Lasers & Sources

    FIBER-BASED COMPONENTS: Coherent beam combination moves to the femtosecond-pulse regime

    John Wallace
    Oct. 1, 2011
    The optical outputs of two—and potentially more—femtosecond fiber amplifiers seeded by the same oscillator can now be coherently combined, providing a way to greatly increase ...
    FIGURE 1. The absorption curves for silicon are plotted for an energy density of 1 J/cm2. For pulse durations of 6 ps (left) the linear absorption is dominant above the nonlinear absorption. Even at 500 fs (right) the nonlinear absorption is too low to reach the desired 1 µm scale optical penetration depth.
    Lasers & Sources

    ULTRAFAST LASERS: High-power pico- and femtosecond lasers enable new applications

    Oct. 1, 2011
    Ultrafast laser pulses with proper energy density and wavelength can now be used for processing materials where thermal influence must be minimized, including drilling metals ...
    (Courtesy of Nanosensors)
    FIGURE 1. The cantilever and sharp tip span the tines of a quartz tuning fork in the Akiyama-probe resonant surface-probe sensor. The tines vibrate in an opposing motion while the cantilever vibrates perpendicular to the tine motion.
    Positioning, Support & Accessories

    NANOPOSITIONING: Piezoelectric nanopositioners forge low-cost atomic force microscope

    Oct. 1, 2011
    In the nanopositioning industry, prices continue to fall as resolution, linearity, and reliability improve. Engineers can now use standard optical components and off-the-shelf...
    FIGURE 1. Commercial multiphoton microscope with the scan head attached to a conventional upright fluorescence microscope. The upright is the preferred option for in vivo imaging, frequently with the use of water immersion lenses.
    Research

    BIOMEDICAL IMAGING: Has multiphoton imaging come of age?

    Oct. 1, 2011
    Advances in ultrafast lasers, beam delivery systems, and optics are helping researchers develop new applications of nonlinear microscopy and improving prospects for clinical diagnosis...
    FIGURE 1. A tunable colloidal quantum-dot photo field-effect transistor includes gold electrodes on glass, a layer of aluminum-doped zinc oxide (AZO) serving as an electron-accepting channel (EAC), and a submonolayer of colloidal quantum dots (CQDs). Incident light causes dissociation of electrons at the AZO/CQD interface, which are harvested by applying a voltage across the electrodes.
    Detectors & Imaging

    QUANTUM-DOT DETECTORS: Colloidal quantum-dot phototransistor could become solar-cell junction

    John Wallace
    Oct. 1, 2011
    A submonolayer of lead sulfide quantum dots on aluminum-doped zinc oxide forms a photo field-effect transistor; its bandgap is tunable to wavelengths suitable for use in photovoltaics...
    Research

    PV polarizer technology lets cell phones charge themselves

    Gail Overton
    Oct. 1, 2011
    An engineering team at the University of California–Los Angeles (UCLA) Henry Samueli School of Engineering and Applied Science has developed a polarizing organic photovoltaic ...
    Research

    Two-photon absorption allows fast modulation in silicon-core fiber

    John Wallace
    Oct. 1, 2011
    Scientists from the Optoelectronics Research Centre, University of Southampton and Penn State University have created an optical fiber with a hydrogenated amorphous silicon (a...