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  • Volume 52, Issue 01

    • Volume 52, Issue 01

    1601 Lfw Nb 6
    Gail Overton
    Feb. 1, 2016
    Dispelix Oy, a spinoff of research organization VTT Technical Research, has developed a see-through, near-to-the-eye smartglass display that uses novel waveguide-based optics ...
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    John Wallace
    Feb. 1, 2016
    Ranjith Nair and Mankei Tsang of the National University of Singapore have proposed a framework for estimating the separation of two incoherent point sources of arbitrary closeness...
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    Gail Overton
    Feb. 1, 2016
    Typical fluorescence-based endoscopic imaging cameras consume large amounts of power and are limited to laboratory-scale applications because of their bulky size.
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    Gail Overton
    Feb. 1, 2016
    Conversion of abundant, common carbon into bulk diamond is typically accomplished through volcanic action or laboratory environments at very high temperatures and pressures, while...
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    John Wallace
    Feb. 1, 2016
    The need for high-power green laser sources for welding copper has driven the development of frequency-doubled disk and fiber lasers emitting in the 515-532 nm spectral region...

    More content from Volume 52, Issue 01

    (Courtesy of ITRI)
    When combined with a PCOLED plasmon-coupled nanostructure layer, a green phosphorescent OLED layer (a) produces blue light (b). Combined with a red OLED (or alternatively with a red-shifting nanostructure), the result is a white-light OLED (c). These light emitters can have different hues such as warm (2039 K) or cool white (6000 K) (d). The technology is already being used to produce passive-matrix OLED displays (e).
    John Wallace
    Feb. 1, 2016
    The thin-film nature of white organic light-emitting diode (OLED) lighting elements allows them to be made into large-area, glare-free lamps and luminaires shaped unlike any other...
    FIGURE 1. A blue LED can excite phosphors emitting at longer wavelengths and contribute blue light to make white light (a), and red, green, and blue lights can be combined to generate white light-adjusting relative outputs of the three colors can tune the wavelength (b). Other variations are possible.
    Jeff Hecht
    Feb. 1, 2016
    Making the most of LED light sources requires refinements in color measurement and standards, and an understanding of how the color sensitivity of the eye varies in the range ...
    FIGURE 1. Precise control over peak power, marking speed, and number of pulses allows for color laser annealing (printing) on stainless steel with immense detail. Examples show a number of obtainable colors (a) and the high printed quality of a complex pattern (b).
    Feb. 1, 2016
    A compact, stable nanosecond-pulse DPSS marking laser with all-in-one thermal packaging is intended for widespread use by everyday users.
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    Gail Overton
    Feb. 1, 2016
    Most economic forecasters agree that the global economy is slowing. However, the attractive ROI and energy efficiency of today's laser technologies just may keep laser sales ahead...
    (Courtesy of OSA)
    The attenuated-total-internal-reflection (ATIR) spectrum for surface-plasmon polariton excitation for a properly oriented prism assembly (containing a gold thin film on the hypotenuse) highlights how sensitive the reflectivity can be to the slightest change in angle for certain angles (left). The optical system in which the prism is placed (right) also contains a deformable mirror (DM; to create a desired wavefront), a Hartmann-Shack wavefront sensor (HS WFS) for comparison, and a CCD camera to capture wavefront-slope images (insets at right).
    John Wallace
    Feb. 1, 2016
    Wavefront sensors are at the heart of most adaptive optics (AO), which are used widely in systems ranging from astronomical telescopes, optical coherence tomography (OCT), and...
    FIGURE 2. A cascade of five beam expanders with M=21 and a design wavelength of 532 nm is used at a 600 nm wavelength (top). The wavefront, divergence, P-V, and RMS of the wavefronts after passing through the given number of beam expanders are compared (bottom).
    Feb. 1, 2016
    Single-element beam expanders containing an aspheric surface can be used in cascade to create different magnifications; an added lens adjusts for wavelength-change effects.
    (Courtesy of UCLA)
    A terahertz quantum-cascade (QC) vertical-external-cavity surface-emitting laser (VECSEL) consists of an active metasurface reflector and output coupler (a); the metasurface is patterned with a metal-metal waveguide subcavity array (b). A scanning-electron microscope (SEM) image shows the metasurface reflector and its 1.5 × 1.5 mm2 active area (c).
    Gail Overton
    Feb. 1, 2016
    Since the demonstration of continuous-wave (CW) quantum-cascade (QC)-based terahertz lasers in the early 2000s, researchers have continued to increase power-output levels to the...
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    John Wallace
    Feb. 1, 2016
    Because of its high refractive index of about 1.77, the sapphire-based aplanatic numerical-aperture-increasing lens (aNAIL) can produce a higher resolution than ordinary optics...
    (Courtesy of Florida State University)
    In the layered manganese oxide material called birnessite (a), substitution of different cations at three potential sites (b) allows tailored bandgap tuning such that the material can trap light and be used in a photosynthesis-type process to generate energy.
    Gail Overton
    Feb. 1, 2016
    Splitting water (H2O) through an oxidation process into hydrogen fuel and oxygen or converting carbon dioxide (CO2) into a fuel such as methanol requires a large amount of energy...
    FIGURE 1. Masked point-source LED during production, with and without reticle.
    Feb. 1, 2016
    Applications requiring extremely well-defined illumination patterns may benefit from LEDs modified to control the shape and size of the light aperture.
    (Courtesy of Hans Bjelkhagen)
    An OptoClone of a Faberge Imperial Easter Egg, the 1897 Coronation Easter Egg, appears to viewers as if it were the object itself.
    John Wallace
    Feb. 1, 2016
    Done correctly, a high-quality photographic-emulsion-based hologram can present a stunning 3D image that closely replicates the appearance of an actual object.
    Dr. Y.S. Liu
    Milton Chang
    Feb. 1, 2016
    Dr. Y.S. Liu, formerly Vice Chancellor of the University System of Taiwan and Macronix Professor at the Institute of Photonics of National Tsing Hua University (NTHU), is Distinguished...
    FIGURE 1. A typical spectroscopy system consists of a light source, optical fiber, spectrograph, and a CCD detector.
    Michael Case
    Feb. 1, 2016
    Accurate, repeatable wavelength and intensity information is possible for a spectrometer using an LED source and nonlinear optimization by taking into account variations in system...
    (Courtesy of Nufern)
    FIGURE 1. A near-infrared pulsed laser signal is sent down an optical fiber, creating Rayleigh, Brillouin, and Raman backscattering—all of which are used for different types of distributed sensing, as seen in this spectral schematic. Brillouin and Raman scattering occur via the Stokes and anti-Stokes processes.
    John Wallace
    Feb. 1, 2016
    Optical fibers used for sensing can measure temperature, strain, pressure, sound, electrical current, and even the 3D shape of the fiber itself.
    FIGURE 1. Conceptual mapping from a point source to a freeform surface (P) to a set of target points (yn). The surface normals (Pn) are set to send the incident rays to their corresponding target points. The surface is then created using a B-spline surface interpolation [2].
    Feb. 1, 2016
    Newly developed tools integrated with commercial illumination software quickly create freeform reflective and refractive surfaces.