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    • Volume 45, Issue 5

    More content from Volume 45, Issue 5

    Images courtesy of Schott AG, High Q Laser Innovation GmbH, iie GmbH, Amtron GmbH
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    Current travel restrictions at many firms may have kept some of us at our desks instead of out on the road, but they certainly haven’t dampened the enthusiasm of organizers of...
    May 1, 2009
    (Courtesy of the University of Augsburg)
    FIGURE 1. Blue, green, and red OLEDs are used as light sources in an experimental SPR sensor. The active area of the OLEDs is 10 mm long and 0.5 mm wide, so that the OLEDs can be regarded as linear light sources.
    Organic light-emitting diodes offer much more than displays and lighting: they are perfectly suited as integrated light sources for many sensing applications.
    May 1, 2009
    FIGURE 1. In this quasi-optical terahertz system, an indium tin oxide (ITO) plate is used to couple in the femtosecond-laser beam for detection of terahertz radiation.
    Contrary to popular belief, off-the-shelf software can indeed tackle the unusual requirements of terahertz imaging—and in the process of optimizing such systems, help push terahertz...
    May 1, 2009
    FIGURE 1. Existing applications for lasers within the solar industry include c-Si edge isolation (left) and thin-film patterning (right).
    Changes in solar supply-demand dynamics, coupled with new tooling requirements for next-generation photovoltaics, are likely to increase adoption rates of lasers used in production...
    May 1, 2009
    FIGURE 1. In the NIST-F1 cesium-fountain atomic clock six infrared lasers collect cesium atoms into a group and cool them to millikelvin temperatures. Then two vertical lasers “toss” the cesium atoms upward about a meter, passing through a cavity where they are irradiated by microwaves. When the lasers are switched off, the atoms fall back through the microwave cavity and through a laser beam that probes the atoms to see if the microwaves changed their energy level.
    The best optical clocks can already beat the best cesium atomic clocks for cutting-edge laboratory measurements; the next challenge is to develop more practical versions for application...
    May 1, 2009
    (Courtesy Institute of Physics, Chinese Academy of Sciences)
    A normalized second-order intensity fluctuation correlation function (Δg(2)) can be mathematically translated into a ghost image of pinholes in a copper foil, as shown in the actual cross section here (top). A simulation of a differently sized double-slit ghost image shows that away from the lensless imaging conditions the image becomes blurred (bottom).
    Ghost imaging is as spooky as it sounds, and is indeed related to “spooky action at a distance” and quantum-entangled photons.
    May 1, 2009
    FIGURE 1. A basic integrator lens array is shown at perpendicular (left), maximum angle of incidence (center), and illumination outside the acceptance (or integration) angle (right). A source with an arbitrary irradiance distribution (gray shape, bottom left) is transferred into a uniform irradiance distribution on the receiver by a symmetrical microlens array (bottom).
    Formed by a combination of reflective and/or refractive surfaces and organized in corresponding pairs, a Köhler integrator can be superimposed onto designed optical surfaces to...
    May 1, 2009
    FIGURE 1. In a microphotoluminescence spectroscopy setup laser light is directed through a microscope objective and focused onto the sample (left). The sample rests in a cryogenic environment and is mounted to a cryogenic compatible stage. The photoluminescence (PL) is collected by the objective and separated from the laser light by a dichroic beamsplitter (BS). The PL is then spectrally filtered by a bandpass filter (BP). The location on the sample surface is monitored by an imaging CCD camera and the excitation power is monitored at the photodiode (PD). A Hanbury-Brown and Twiss (HBT) interferometer with a time correlator is used to verify single-photon emission. Photons are separated at the 50:50 beamsplitter (BS) and detected by the single-photon detectors (SPDs). The time between successive arrival times, Δt, is tabulated by the time correlator (upper right). A histogram of detection events using the HBT setup with a quantum-dot SPS under pulsed excitation shows a dramatic lack of events at Δt = 0, which indicates the single-photon character of the emission (lower right).
    Quantum-dot-based single-photon sources are fast and efficient and remain at the forefront of candidates for use in quantum information schemes.
    May 1, 2009
    FIGURE 1. With the integration of CARS microscopy into the experimental setup, complex three-dimensional structures fabricated with TPP (shown in SEM images) can be characterized and inspected during the fabrication process.
    Compared to scanning-electron microscopy, CARS microscopy produces a richer data set and is more conducive to in situ testing of microstructures created using two-photon polymerization...
    May 1, 2009
    (Courtesy of RPI)
    A three-layer broadband GRIN antireflection coating for solar cells has a 49 nm dense TiO2 inner layer, a 99 nm layer of slightly porous SiO2, and a 360 nm layer of very porous SiO2.
    Typical silicon (Si) solar cells appear bluish for a reason. Because of the high refractive index of Si, the material’s bare untreated surface reflects 30% or more of the light...
    May 1, 2009
    (Courtesy of Ocean Thin Films)
    A microphotograph shows images of dichroic filters manufactured in a hybrid thin-film lithographic technique for a new, lower-cost megapixel multispectral imager. The filters can be custom designed to provide color images for low-light-level scenes (left) or for additional infrared filtering (right). Rectangular elements are 19 × 33 µm in size.
    By using patterned dichroic filters fabricated with combined thin-film and lithography techniques and a CCD or CMOS sensor architecture, Ocean Optics (Dunedin, FL) and Ocean Thin...
    May 1, 2009
    (Courtesy of Harvey Mudd College and Los Alamos National Laboratory)
    An optical refrigerator depends on removal of high-energy photons to cool a special laser-pumped material. In the simplest implementation, this is accomplished by directly attaching a thermal link that is then butt-coupled to a heat load (top). To improve refrigeration efficiency, several versions of optical-waveguide tapers and lens elements can be used as thermal links to remove absorptive photons (bottom).
    Back in 1995, Laser Focus World reported on a developing optical refrigeration technique from Los Alamos National Laboratory (Los Alamos, NM) in which 1020 nm light from an ytterbium...
    May 1, 2009
    Most hyperspectral imagers use a linear or two-dimensional array of photodetectors, with the exception of certain pushbroom scanning mechanisms that use a fixed diffraction grating...
    May 1, 2009
    (Courtesy of Andreas Blug)
    A full image-based feedback system continuously monitors the keyhole welding process to make sure the weld is adequate.
    Keyhole welding, one of the most common means of laser welding in industry, has gotten a quality-control boost in the form of a new image-processing method developed by researchers...
    May 1, 2009
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    For the latest in new products, see Photonics Products Online on our home page and at www.laserfocusworld.com/exclusives/highlights.html
    May 1, 2009
    Researchers in China say they have developed a new type of light-emitting diode (LED) made from inexpensive, plastic-like organic materials.
    May 1, 2009
    Wavelength-tunable microelectromechanical systems (MEMS)-based gratings with blazed surfaces are not new; however, the high diffraction efficiency needed for telecommunications...
    May 1, 2009
    (Courtesy of IOP Publishing)
    The end of the mask fiber is patterned with stripes of varying width (top). The developed pattern produced on the target fiber shows a resolution of about 2 µm (center and bottom).
    About three years ago, researchers at Vrije Universiteit (Amsterdam, The Netherlands) created a tiny interferometric sensor that fit on the end of an optical fiber; the so-called...
    May 1, 2009
    For ten years, the Optics Suitcase, a learning module sponsored by the Rochester local section of the OSA, has been helping presenters around globe demonstrate that optics can...
    May 1, 2009
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    The Lambda XL is a broad spectrum, highly stable light source (1% peak-to-peak fluctuations) with expected lamp life in excess of 10,000 hours.
    May 1, 2009
    The Kindle 2 is a very nifty device that leaves its competition eating dust, but it has so many near misses that I’m forced to conclude that the Kindle is really more like a badly...
    May 1, 2009
    A new report from our sister company, Strategies Unlimited (Mountain View, CA; see www.laserfocusworld.com/articles/357230) predicts that sales of industrial lasers in 2009 could...
    May 1, 2009
    1304qa Chang New
    Q: I need some career advice after just losing my job at the third failed medical-diagnostic startup I have worked for.
    May 1, 2009
    (Courtesy of ICFO)
    FIGURE 1. A temperature-mapping procedure is demonstrated on a 2 x 2 µm2 gold nanostructure (left, SEM image) heated under IR illumination. Two detectors adapted on a confocal microscope map the two polarization components (center) of the fluorescence emitted from the molecules surrounding the gold structure. From these two images, the anisotropy and the temperature variations throughout the medium of interest are rendered in real time (right).
    An optical technique has been developed that enables fast and accurate temperature mapping around nanosources of heat. This breakthrough should give an impetus to novel branches...
    April 24, 2009