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  • Volume 44, Issue 5

    • Volume 44, Issue 5

    Optics

    Nonlinear optics measure phase-velocity distribution

    May 1, 2008
    Although it is well understood theoretically that a focused Gaussian beam will present phase-velocity variations across its waist both radially and axially, experimental verification...
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    Research

    Surface patterning uses BLAST technique

    May 1, 2008
    Numerous laser-based methods exist for creating patterns and textures on a substrate, including traditional lithography, direct-write methods, and exposure through self-assembled...
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    Detectors & Imaging

    Type II semiconductor superlattice photodetectors new alternative to HgCdTe

    May 1, 2008
    While mercury cadmium telluride photodiodes and quantum-well infrared photodetectors are well established in military and other applications, the performance of these detectors...
    Research

    Inside-out EM cloak improves upon existing theory

    May 1, 2008
    The advent of invisibility cloaks for electromagnetic (EM) waves has arisen from clever theoretical advances in transformation optics, for which exit EM waves can be made identical...
    Research

    Metal surface plasmons enhance single-cell fluorescence

    May 1, 2008
    The use of fluorophore-metal interactions has the potential to dramatically increase the detectability of single fluorophores for both single-molecule detection (SMD) and fluorescence...

    More content from Volume 44, Issue 5

    (Courtesy of AFE Technology Coatings)
    FIGURE 1. A head-up display combiner with a rugate coating is used in aircraft to reflect a monochromatic green display.
    Optics

    Optical coatings: Rugate coatings enhance performance of head-up displays

    May 1, 2008
    A head-up display (HUD) provides the ability to project information onto a transparent screen so that it appears to be floating in space as a virtual image.
    FIGURE 1. In confocal fluorescence microscopy, the illuminating light (blue) is focused through a short-focus lens into a sample, where it induces fluorescence (red), which the lens collects and directs back toward the light source. A dichroic beamsplitter transmits the illuminating beam, but reflects the fluorescence toward a detector, where a spatial filter blocks light from other points. Note that light from other planes in the sample (dashed line) is strongly attenuated by the spatial filter.
    Optics

    Photonic Frontiers: Microscopy Techniques - The quest to see inside living cells is driving new optical microscopy

    Jeff Hecht
    May 1, 2008
    Powerful new techniques use fluorescence imaging and nonlinear techniques to probe cells; developers hope to produce a new generation of clinical tests.
    FIGURE 1. In the modified fabrication method of hollow-core photonic-bandgap fibers, several hundred capillaries each 1 to 2 mm in diameter are stacked to create a preform. The core is formed by simply omitting some capillaries from the middle of the stack (1). The preform is drawn down to canes preserving the structure—the image shows an optical microscope image of a cane cross section. The diameter is approximately 3 mm. No central tube has been used to define the hollow core (2). In a final step the cane is inflated by being pressurized from the top while being drawn down into fiber. The scanning-electron-microscope image of the final fiber shows the thinner wall of glass around the fiber core (3).
    Fiber Optics

    SPECIALTY FIBERS: Novel process eases production of hollow-core fiber

    May 1, 2008
    Optical fibers are typically formed from two glasses: the first, with a higher refractive index, runs down the middle of the fiber, forming the core in which light is trapped;...
    (Courtesy of National Research Council of Canada)
    FIGURE 1. A high-resolution 3-D color laser scanner mounted on a translation stage was used to scan the Mona Lisa. The scanner uses red, green, and blue wavelengths as the laser source, which, when superimposed in the scanning system, results in the projection of a white, 50- to 100-µm-diameter laser spot on the object.
    Test & Measurement

    Optoelectronic Applications: Nondestructive Testing - Laser-based instrumentation sheds new light on old art

    Kathy Kincade
    May 1, 2008
    With the advent of increasingly cost-effective, high-resolution optical-imaging technologies, art historians are delving deeper into the world of forensic science.
    A typical light engine comprises a lamp module and delivery optics. The Lumenor light-pipe geometry integrates a significant fraction of the light, resulting in high external efficiencies that are optimized by the design of the lamp module (including the excitation source) and the unique geometric shape of the pipe. Increased power levels can be obtained by scaling the light pipe and associated excitation.
    Research

    BIOMEDICAL OPTICS: Novel light engine challenges lasers, lamps, and LEDs in life sciences

    John Wallace
    May 1, 2008
    Lumencor (Beaverton, OR), a year-old company focused on the development of novel light engines, is targeting life-science instrumentation with its initial products and is gearing...
    Research

    Free-electron laser selectively targets acne sebum structure

    May 1, 2008
    Fernanda Sakamoto, MD, of Harvard Medical School and her colleagues at the Wellman Center for Photomedicine at Massachusetts General Hospital (Boston, MA) are using a tunable ...
    (Courtesy of Quantum Communications Victoria)
    Materials Engineer David Simpson from Quantum Communications Victoria (QCV) observes the growth of diamond nanocrystals in a microwave plasma-enhanced chemical-vapor-deposition reactor. A patented technique for optical pumping of single-atom nitrogen defects in the diamond nanocrystals (inset) creates an excited state that generates single-photon emission at 700 nm, allowing show-floor operation of QCV’s newly released SPS 1.01 single-photon source.
    Research

    OFC / NFOEC 2008: Telecom is poised to go terabit

    Jeff Hecht
    May 1, 2008
    Now that fiber-to-the-home (FTTH) and 40 Gbit/s systems are being commercially deployed, it seems that the telecom industry is already looking ahead to terabit networks to feed...
    Detectors & Imaging

    Silica-on-silicon chips beget quantum circuits

    May 1, 2008
    Single-photon detectors have enabled strides toward viable quantum information processing.
    (Courtesy of Trumpf-Laser)
    The thin-disk scheme generated a CW background near 1027 nm. The autocorrelation trace and optical spectrum of the laser output show a 1.36 ps pulse length and 0.88 nm pulse width at a center wavelength of 1030.3 nm.
    Research

    PICOSECOND LASERS: Thin-disk laser oscillator generates record-energy short pulses

    Valerie Coffey-Rosich
    May 1, 2008
    Optimizing the power of pulses in the picosecond regime is important for advances in micromachining, direct pumping of parametric devices, and high-field physics.
    (Courtesy of Friedrich-Schiller-Universität Jena)
    FIGURE 1. A millijoule-level high-repetition-rate fiber chirped-pulse amplification system includes an optical isolator (ISO), acousto-optical modulator (AOM), and specialized photonic-crystal fiber (PCF).
    Fiber Optics

    High-power Fiber Lasers: Ultrafast fiber laser reaches gigawatt peak powers

    Jens Limpert
    May 1, 2008
    The power-handling capabilities of the main amplifier in a fiber laser reveal a potential performance of gigawatt peak power at megahertz repetition rate.
    (Courtesy of Microvision)
    FIGURE 1. In miniature projector displays, a single MEMS mirror rotates biaxially to raster-scan a two-dimensional image—much like old TVs but with photons instead of electrons.
    Optics

    PICOPROJECTORS: Nanosecond modulation makes cell-phone projectors possible

    May 1, 2008
    Mobile laser-projectors based on MEMS will soon enable consumers to project full-color, high-resolution images from mobile phones, laptop computers, personal media players, and...
    Lasers are used to imprint a wood-grain design onto the surface of medium-density fiberboard, giving it the appearance of expensive wood.
    Lasers & Sources

    MATERIALS PROCESSING: Laser puts a nice-looking coat on medium-density fiberboard

    D. Jason Palmer
    May 1, 2008
    Medium-density fiberboard, or MDF, is probably one of the most versatile and useful wood products.
    Research

    Fused-silica damage threshold established at 1064 nm

    May 1, 2008
    The optical-damage threshold in bulk fused silica is important for establishing the performance limits of high-power laser systems, but the mechanism is poorly understood.
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    Test & Measurement

    NIST microscope tracks nanoparticles in 3-D

    May 1, 2008
    A patent-pending microscope substrate design developed at the National Institute of Standards and Technology (NIST; Gaithersburg, MD) allows nanotechnology researchers to track...
    (Courtesy of Joan Edwards and Dwight Whitaker)
    FIGURE 1. A nine-frame image sequence shows the explosive discharge of spores from Sphagnum moss recorded at 10,000 fps, thanks to the capabilities of modern high-speed digital cameras.
    Research

    High-Speed Imaging: High-speed images capture processes in botanical systems

    May 1, 2008
    Advances in high-speed imaging systems make it possible to record ultra-high-speed movements of biological systems (less than 1 ms) under lighting conditions that do not damage...