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  • Volume 45, Issue 8

    • Volume 45, Issue 8

    (Courtesy of SLAC)
    FIGURE 1. A dozen LCLS undulators (silver) installed along the undulator hall were enough to demonstrate initial lasing in April.
    Research

    PHOTONIC FRONTIERS: Linac Coherent Light Source begins operation

    Jeff Hecht
    Aug. 1, 2009
    Powered by electrons from a kilometer-long linear accelerator, the Linac Coherent Light Source at the SLAC National Accelerator Laboratory opens this month, giving scientists ...
    Th Ge On 0809 01
    Research

    Ge-on-Si direct-band-gap LED lays groundwork for group-IV laser

    Aug. 1, 2009
    A 1.6-µm-emitting germanium-on-silicon (Ge-on-Si) LED developed by researchers at Stanford University (Palo Alto, CA) could be the key to a Si-compatible group-IV semiconductor...
    Research

    Femtosecond-laser treatment makes tungsten lamp filament more efficient

    Aug. 1, 2009
    A femtosecond-laser nanostructuring technique that blackens metal has been applied by its inventors to tungsten lamp filaments, enhancing their emission efficiency to near 100...
    Detectors & Imaging

    Laser technology generates bias-free, true random numbers

    Aug. 1, 2009
    Although the generation of true random numbers is crucial in modern digital electronic information systems for statistical sampling, cryptography, and other applications, the ...
    Research

    Fiber with frozen-in stress has 84 µm strictly single-mode diameter

    Aug. 1, 2009
    Researchers at IMRA America (Ann Arbor, MI) have created a single-mode optical fiber with the largest core ever.

    More content from Volume 45, Issue 8

    Th Cars 0809 01
    Research

    ULTRAFAST LASERS: CARS ultrafast light source is hands-free

    Aug. 1, 2009
    A turnkey, single-box, solid-state-laser-based light source for coherent anti-Stokes Raman scattering (CARS) microscopy eliminates the need for two highly synchronized Ti:sapphire...
    Th Laser 0809 01
    Detectors & Imaging

    LASER, WORLD OF PHOTONIC REVIEW: Munich sends optimistic message

    Barbara Gefvert
    Aug. 1, 2009
    One of the more intriguing aspects to this year’s Laser, World of Photonics exhibition and conference in Munich, Germany, was the apparent sense of calm that has settled over ...
    (Courtesy of Toptica and High Finesse)
    FIGURE 1. Toptica’s most recent offering is the Ultimate 2 in the WSU series of wavelength meters, offering the best absolute accuracy on the market of up to ±2 MHz for 370 to 1100 nm (5 × 10-6 nm resolution at 800 nm wavelength), achieved when using a calibration laser with a linewidth known to better than 1 MHz. The Fizeau-interferometer-based system for pulsed or CW lasers allows high-speed measurement and feedback control of up to eight lasers with a repeatability of up to 500 kHz.
    Test & Measurement

    WAVELENGTH METERS: How to select a wavelength meter

    Valerie Coffey-Rosich
    Aug. 1, 2009
    When high-accuracy wavelength measurement is required, comparing products is easier if you understand how manufacturers specify the accuracy–whether in megahertz, picometers, ...
    Detectors & Imaging

    Ultrafast grows as lasers shrink

    Stephen G. Anderson
    Aug. 1, 2009
    Many of the technical papers and product announcements at recent industry conferences serve to underscore the considerable engineering and design effort being undertaken by laser...
    (Image courtesy of Toptica Photonics)
    Th Astronomy 0809 01
    Research

    ASTRONOMY: Sodium guidestar laser uses fiber Raman technology

    Stephen G. Anderson
    Aug. 1, 2009
    Large ground-based telescopes can use a sodium “guidestar” to enable active compensation of atmospheric disturbances using adaptive optics and making possible high-resolution ...
    Th 0908lfw Fea2 Femtofit
    Research

    INNOVATION AWARD: BioPhotonic Solutions takes home PhAST/LFW Innovation Award

    Aug. 1, 2009
    The annual PhAST/Laser Focus World Innovation Award ¿honors groundbreaking photonics products.
    A 532 nm pulse from a nanosecond Nd:YAG laser revives a faded plasma filament that was created by a femtosecond Ti:sapphire laser. A third pulse at 1064 nm (not shown) can then further increase the revived filament’s free-electron density to beyond that of the original filament.
    Research

    PULSED LASERS: Laser pulses rejuvenate faded plasma filaments

    John Wallace
    Aug. 1, 2009
    Plasma filaments generated by femtosecond-laser pulses in air are not just a spectacular effect–they are potentially useful too.
    FIGURE 1. A typical multiphoton-microscopy (MPM) setup includes the excitation laser, scanning and imaging optics, filters, and photomultiplier-tube (PMT) detector.
    Optics

    OPTICAL FILTERS FOR BIO-OPTICS: Custom filters improve image quality of multiphoton microscopy

    Aug. 1, 2009
    In multiphoton microscopy, ultra-high-transmission filters with deep blocking and steep sides can effectively block all the excitation light while transmitting the precious fluorescence...
    Under conditions typically used in dynamic live-cell imaging, sCMOS provides a much wider field of view and improved signal-to-noise ratio at approximately 70 frames/s (left), compared with interline CCD’s 11 frames/s (above).
    Detectors & Imaging

    CMOS IMAGERS: sCMOS aims to topple CCD for scientific applications

    Barbara Gefvert
    Aug. 1, 2009
    Choosing a rapid frame rate has traditionally meant compromising on other capabilities such as wide dynamic range.
    The dependence of bending loss for an experimental fiber (at a bending radius of 5 mm and a wavelength of 1550 nm) reaches a theoretical minimum when b/a is 2.12. The b/a for the fabricated fiber was very different–0.98–but the bending loss was only slightly higher than the minimum.
    Research

    FIBER FABRICATION: Single-mode fiber has very low bending loss

    John Wallace
    Aug. 1, 2009
    One can imagine the twists and turns taken by an optical fiber as it is routed in a fiber-to-the-home application.
    (Courtesy of the University of Glasgow)
    Imaging cameras enable an operator to feel the actual measured forces exerted on a bead in an optical trap as in interacts with a silicon cube.
    Research

    OPTICAL TWEEZERS: Imaging lets optical tweezers ‘feel the force’

    Gail Overton
    Aug. 1, 2009
    A low-cost, imaging-based force-feedback device has been created that allows users to perceive real Brownian motion and viscosity when using optical tweezers; in effect, the user...
    (Courtesy of Headwall Photonics)
    Hyperspectral instruments generate high-contrast images of latent fingerprints while also yielding chemical “signature” information about material left behind that could be associated with the fingerprint. This image shows that a fingerprint can be nondestructively viewed and analyzed with the spectral signature identified at three discrete points within the field of view.
    Detectors & Imaging

    FORENSICS: Fingerprint analysis goes hyperspectral

    Gail Overton
    Aug. 1, 2009
    ChemImage (Pittsburgh, PA), an analytical-imaging company, recently made improvements to its CONDOR Hyperspectral Imaging System that allow the system to see enhanced ridge detail...
    Optics

    Tiniest two-photon MEMS microscope performs brain imaging

    Aug. 1, 2009
    Researchers at Stanford University (Stanford, CA) have developed an incredibly small two-photon microscope imager that uses a microelectromechanical systems (MEMS) laser-scanning...
    (Courtesy of SiOnyx)
    FIGURE 1. Black silicon structures are fabricated using an industrial CMOS process.
    Detectors & Imaging

    IR DETECTORS: Black silicon sees further into the IR

    Aug. 1, 2009
    Femtosecond-laser engineering of silicon with a CMOS-compatible process results in the creation of black silicon, which offers high optical sensitivity in the near- and short-...
    (Courtesy of DESY)
    In the “light shining through walls” experiment, the laser is at left, the HERA dipole magnet at center, and the detector at right.
    Research

    LASER PHYSICS: ‘Light shining through walls’ experiment gets a boost

    D. Jason Palmer
    Aug. 1, 2009
    In a small experiment at the DESY synchrotron source (Hamburg, Germany), a detector is effectively staring at a wall, waiting for light to come through.