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  • Volume 44, Issue 1

    • Volume 44, Issue 1

    Detectors & Imaging

    Iridium (III) device emits red light efficiently

    Jan. 1, 2008
    Flexible displays have proven inefficient compared to other types of displays and, so far, expensive to fabricate.
    Research

    Researchers propose ‘on-chip’ single-photon gun

    Jan. 1, 2008
    Single-photon sources and detectors are highly desirable for quantum information systems.
    Research

    InGaAs quantum-well lasers provide alternative to 1.55 µm GaAs-based lasers

    Jan. 1, 2008
    Gallium arsenide (GaAs) lasers at 1.3 and 1.55 µm have received a lot of attention in the past several years for their potential as inexpensive, high-speed, uncooled sources for...
    Optics

    Silicon modulators could enable laptop supercomputers

    Jan. 1, 2008
    Scientists at IBM Research (Yorktown Heights, NY) have developed silicon Mach-Zehnder electro-optic modulators so tiny that supercomputers-consisting of thousands of individual...
    Lasers & Sources

    JDSU introduces 10 W single-emitter diode laser

    Jan. 1, 2008
    JDSU (Milpitas, CA) has introduced a new single-emitter diode-laser platform that the company says is the most powerful fiber-coupled diode laser now on the market.

    More content from Volume 44, Issue 1

    FIGURE 1. Five Shack-Hartmann wavefront sensors-one on-axis and four off-axis-measure the quality of mobile-phone camera lenses. Light from a multipinhole light source is used to illuminate the lens, and the five cameras record the spot patterns. A calibration image is taken using parallel light from a high-quality lens. After analysis, the good and bad lenses are automatically sorted out. The whole operation takes less than five seconds. The off-axis angles can be defined by the user.
    Optics

    TEST & MEASUREMENT: Wavefront sensing goes off-axis

    Jan. 1, 2008
    A new generation of diagnostic instruments based on the Shack-Hartmann method can be used to measure the optical quality of single or complex lenses, measuring on-axis as well...
    (Courtesy of Coherent)
    FIGURE 1. With PermAlign technology, each optic in a diode-pumped solid-state laser cavity is rigidly soldered to a ceramic base.
    Fiber Optics

    LASERS FOR MARKING: DPSS lasers rival fiber lasers for marking applications

    Jan. 1, 2008
    A unique monolithic mounting system results in a highly stable diode-pumped solid-state laser source that can address a wider spectrum of marking applications than fiber lasers...
    FIGURE 1. A basic field-effect transistor consists of a source and drain of charge carriers that connect to a channel controlled by a gate (top). A fundamental standing-charge-density oscillation, known as a plasmon, sloshes between two boundaries (bottom left). Increased current causes a higher harmonic of the fundamental plasmon, splitting the group in two (bottom right). Like a spring constant, increasing the carrier density in the channel increases the resonant frequency.
    Detectors & Imaging

    NEXT-GENERATION DETECTORS: Plasmon grating-gate devices have potential as tunable terahertz detectors

    Jan. 1, 2008
    Plasmon-based grating-gate detectors based on hot-electron bolometer mixers are being explored as tunable detectors of terahertz radiation—the next big thing in security applications...
    (Courtesy of University of Rochester)
    A 370-nm-diameter latex sphere captured in the central defect (685-nm-diameter) of a two-dimensional photonic-crystal microcavity (top) causes a redshift of approximately 4 nm in the spectral signature of the sensor (bottom). An increase in the sphere diameter corresponds to an increasing redshift.
    Optics

    OPTICAL SENSORS: Nanoscale microcavity detects single particles

    Gail Overton
    Jan. 1, 2008
    One-dimensional photonic crystals and photonic-crystal microcavities have already been used for the detection of DNA, proteins, and even bacteria.
    FIGURE 1. The current response for a commercially available amorphous-silicon photodiode as a function of illumination follows an exponential curve.
    Detectors & Imaging

    PHOTOVOLTAICS: Spectroradiometer improves accuracy of photovoltaic measurement

    Jan. 1, 2008
    While it is impossible to reproduce the brightness level of the Sun, it is possible to simulate a photovoltaic detector’s response with improved accuracy by integrating a white...
    Optics

    Retinal flow cytometer tracks circulating blood cells

    Jan. 1, 2008
    A retinal flow cytometer developed by researchers from the Wellman Center for Photomedicine at Massachusetts General Hospital and Harvard Medical School (Cambridge, MA) has demonstrated...
    (Courtesy of Josh Semeter, Boston University)
    FIGURE 1. An aurora was imaged from the Sondrestrom Upper Atmospheric Research Facility with a traditional all-sky (fisheye) white-light imager (left) and the Simultaneous Multispectral Imager (right).
    Detectors & Imaging

    MULTISPECTRAL IMAGING: Segmented tunable filters advance multispectral imaging

    Jan. 1, 2008
    Etched liquid-crystal Fabry-Perot tunable optical filters can provide high-enough spectral resolution for background discrimination and rapid tuning in atmospheric sensing.
    Th 271045
    Research

    Tapered QC lasers reduce beam divergence

    Jan. 1, 2008
    Although mid- to far-infrared quantum-cascade (QC) lasers are ideal for gas sensing, free-space optical communications, and imaging, their high beam divergence (typically about...
    FIGURE 1. The electro-optic efficiency of polymer devices, measured as the r33 coefficient, has more than tripled since 2003, and is now more than 10 times the value for LiNbO3, as shown in this plot by DARPA program manager Dev Shenoy.
    Optics

    PHOTONIC FRONTIERS: NONLINEAR ORGANIC MATERIALS: Designer organic molecules create a new class of nonlinear materials

    Jeff Hecht
    Jan. 1, 2008
    Research on organic nonlinear materials dates back a couple of decades, but those efforts have only recently started paying practical dividends.
    Th 271121
    Research

    ACTIVE SURFACE PLASMONS: Tuning of surface plasmons leads to new optoelectronic devices

    Jan. 1, 2008
    Surface plasmons can be thought of as light waves trapped and traveling along the interface between a metal and a dielectric material.
    (Courtesy of ORC Southampton)
    FIGURE 1. A silica microstructured optical fiber fabricated at the University of Southampton Optoelectronics Research Centre demonstrates the flexibility of sizes and arrangement of holes that can be fabricated in a single fiber.
    Research

    ENDOSCOPIC FIBER: Microfluidic chemical deposition moves optical fiber to the nanoscale

    Jan. 1, 2008
    The use of a novel chemical-vapor-deposition process to integrate metals and semiconductor films in microstructured optical fibers may soon enable nanometer-scale waveguides and...
    (Courtesy of Nature Medicine)
    An optical-frequency-domain image of the coronary artery of a pig shows a metal stent in the artery (blue) and damage to the inner surface of the artery (gray).
    Research

    DIAGNOSTIC IMAGING: Speedy imaging technique moves into human trials

    Peter Gwynne
    Jan. 1, 2008
    A research team at Massachusetts General Hospital (MGH; Boston, MA) has developed a laser-based technique that, because it can visualize deposits of plaque, macrophages, and other...
    Th 0801lfwnbf2
    Optics

    Fiber Bragg gratings switch in nanoseconds

    Jan. 1, 2008
    High-speed switching or tuning of light in fiber Bragg gratings (FBGs) can be applied to Q-switching, cavity dumping, and pulse picking in a fiber laser, among other applications...
    Th 271046
    Lasers & Sources

    Orange-red chromophores produce stable white-emitting OLEDs

    Jan. 1, 2008
    White-light organic and polymer light-emitting diodes (WOLEDs and WPLEDs) show promise for use in full-color displays, liquid-crystal-display backlights, and solid-state lighting...
    Th 0801lfw3f1
    Research

    TERAHERTZ GENERATION: Near-IR lasers may close the terahertz gap

    Jan. 1, 2008
    In seafarers’ maps of Renaissance times, the term terra incognita was used to denote unknown land-areas beyond the known frontiers that were yet to be documented.