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    • Volume 55, Issue 04

    More content from Volume 55, Issue 04

    Content Dam Lfw Print Articles 2019 04 1904lfw Nb 1
    Compressed optical-streaking ultra-high-speed photography (COSUP) uses a digital micromirror device (DMD) and a galvo scanner to reach millions of frames per second for standard...
    April 1, 2019
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    The ninth annual Optics & Photonics Global Salary Report from SPIE shows the continuing rise in income associated with jobs in photonics—along with a few surprises.
    April 1, 2019
    FIGURE 1. For wallpaper samples with an identical pattern (a), the lamp in the image (b) acts as a fiducial to determine the correct orientation of the sample.
    Mechanical fiducials and precise 3D positioning can greatly simplify and improve the metrology tools needed to accommodate the introduction of deterministic surface generation...
    April 1, 2019
    FIGURE 1. Shown at left is the fiber cross-section (top) and refractive index profile (bottom) for a feeding fiber with three guiding regions. Simulations (right) show the beam profile coupled into the guiding regions for different perturbation conditions. The beam homogenizes azimuthally as it propagates in the fiber.
    A newly developed fiber laser provides real-time tunability of beam characteristics directly from the laser output fiber using an all-fiber mechanism.
    April 1, 2019
    Content Dam Lfw Print Articles 2019 04 1904lfw Nov 1 R
    Techniques to reduce the impact of fabrication and assembly tolerances as part of the optimization process result in lower-cost optics for high-volume applications.
    April 1, 2019
    FIGURE 1. Shown is an example of laser-induced damage on the surface of an optic imaged using differential interference contrast (DIC) microscopy.
    For mirrors with reflectance values above 99.5%, measuring total loss through cavity ring-down spectroscopy is more accurate than conventional methods.
    April 1, 2019
    FIGURE 1. A flow chart shows the basic process of image fusion in the spatial domain for a visible and infrared image of the same scene.
    The performance of image-fusion algorithms depends heavily on how spatial information is extracted and processed through a variety of spatial-filtering techniques.
    April 1, 2019
    FIGURE 1. A schematic side view shows an on-chip free-space section created using two waveguide-coupled GRIN lenses (a). The top view (b) shows two integrated GRIN lenses creating a free-space etalon (highlighted in yellow). The cross-section (c) illustrates a U-groove with integrated GRIN lens; the width and depth of the U-groove match the GRIN lens diameter of 125 µm.
    Blending on-chip ultrathin-film elements, nonlinear crystals, polymer interposers, and single-photon detectors, the UNIQORN project aims to develop a quantum system-on-chip methodology...
    April 1, 2019
    Content Dam Lfw Print Articles 2019 04 Cover 2
    Label-free time-resolved (“lifetime”) fluorescence spectroscopy and imaging have demonstrated capability for multiple clinical applications, as evidenced by a new robotic surgery...
    April 1, 2019
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    Editor in chief John Lewis discusses the Laser Market Review & Forecast report and invites you to enjoy Laser Focus World’s April 2019 issue, which includes trends in photonics...
    April 1, 2019
    A laser-cooling crystal is mounted in a vacuum chamber for characterization. A continuous-wave optical parametric oscillator (CW-OPO) provides tunable coherent light, which is split by a beamsplitter to the crystal in the vacuum chamber and to an optical spectrum analyzer (OSA) to measure the OPO’s wavelength. A thermal camera monitors the temperature of the crystal.
    Tm:YLF and Tm:BYF crystals are cooled by mid-IR laser light and can enable cryocoolers and radiation-balanced lasers (RBLs).
    April 1, 2019
    Image credit: CREOL
    The emission spectrum (left column) and the far-field pattern (right column) are compared for a single laser cavity (a), a standard five-cavity laser array (c), and a supersymmetric (SUSY) array with a standard five-cavity array adjacent to a four-cavity superpartner lossy array (e). Similar to the single-element laser mode (b), the SUSY array emission (f) shows suppression of the higher-order modes seen in the standard array (d). Overall, the SUSY array has fundamental-mode operation with a smaller diffraction angle and higher quality factor than a standard laser array.
    By placing a lossy superpartner array of waveguide cavities in proximity to a standard array, one can suppress unwanted higher-order transverse modes and amplify the fundamental...
    April 1, 2019
    Mice who had retinal photoreceptor-binding upconversion nanoparticles (pbUCNPs, which anchor themselves to the inner and outer segments of both rods and cones) injected into their eyes showed pupil constriction when subjected to IR light at 980 nm, demonstrating that their eyes and brain had detected the IR light. In contrast, mice who had polyacrylic acid-coated upconversion nanoparticles (paaUCNPs, which did not anchor tightly to the rods and cones) injected into their eyes showed the normal visible-light pupil response, but no IR response.
    Injected ytterbium- and erbium-containing nanoparticles bind to rods and cones and convert 980 nm light to green light with a 535 nm peak.
    April 1, 2019
    (Courtesy of the Mahadevan-Jansen Lab, Vanderbilt University)
    Parathyroid tissue (upper right) autofluoresces under near-IR light at significantly greater intensity than does any other tissue in the neck.
    Detecting parathyroid tissue using near-IR laser light to induce autofluorescence can aid in distinguishing tissue in surgery.
    April 1, 2019