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    • Volume 53, Issue 06

    More content from Volume 53, Issue 06

    FIGURE 1. As laser energy increases, the necessity of higher quality and precision optics and coatings causes the cost of the beam expander to increase (a). Increasing the input aperture size increases the cost of the beam expander rapidly at larger input apertures because of the nonlinear dependence of aberrations on input beam diameter (b). With a fixed design, increasing the input aperture leads to a decrease in performance as aberrations start to dominate the wavefront (c).
    Beam expansion is essential in many laser systems, so correctly specifying the necessary beam expander to achieve the right performance without excessive cost has become crucial...
    June 12, 2017
    FIGURE 1. The semiconductor membrane is shown glued to the silicon carrier wafer.
    By sandwiching a quantum well or dot membrane between diamond or SiC heat sinks, laser-media cooling is maximized and the need for a reflector mirror is eliminated, extending ...
    June 12, 2017
    FIGURE 1. The first two natural frequencies are shown for a plucked string.
    Through laser Doppler vibrometry, the shape and size of a bell can be optimized through modeling—rather than trial and error—to resonate with the desired harmonious sound.
    June 12, 2017
    FIGURE 1. Four levels of laser diode protection are shown (see table for details).
    Take these steps to protect your laser diodes from electrostatic discharge, excessive current levels, current spikes, and transients.
    June 12, 2017
    FIGURE 1. In this fully diode-pumped ultrafast Ti:sapphire oscillator-amplifier system, the Kerr-lens-modelocked Ti:sapphire oscillator is pumped with a single-emitter 465 nm diode (3.1 W), while the amplifier is pumped by either high-power fiber-coupled 450 nm diodes (up to 100 W), or spatially/spectrally combined 465/450 nm single emitters (up to 30 W), and is cryogenically cooled.
    Consumer-driven technologies breathe life into the material of choice for ultrafast lasers.
    June 12, 2017
    FIGURE 1. The surface definition screen defines the acylinder's surface.
    Optically oriented computer-aided manufacturing software ties together metrology and fabrication for acylinders.
    June 12, 2017
    A team of researchers in Germany has demonstrated 4.3 kW single-mode output from a fiber laser, in which the output was limited only by the input pump power.
    By identifying high-power fiber laser challenges and optimizing the optical fiber accordingly, a 4.3 kW single-mode output has been achieved, with further upscaling and new ultrafast...
    June 12, 2017
    Content Dam Lfw Print Articles 2017 06 1706lfw Ch 1a
    The depth and variety of photonics technologies and products on display is an inspiring reminder of the pivotal role of the largest photonics tradeshow in the world.
    June 12, 2017
    (Courtesy of Fraunhofer ILT)
    Different CO2 laser pulse modes (Q-switched and modulated laser pulses) enable different functions for finishing optical glass materials, from ablation through surface correction polishing (a). The secret is a carefully constructed scan pattern and optimized laser parameters (b), allowing the laser to create complex, freeform structures such as this honeycomb glass element (c).
    Ablation of fused silica and other glass materials can be accomplished using CO2 or ultrafast lasers.
    June 10, 2017
    A free-space graphene-based near-IR electro-optical modulator with a modulation volume of about 5 μm3 consists of a quartz (SiO2) substrate, a copper (Cu) bottom electrode, a hafnium dioxide (HfO2) quarter-wave dielectric layer, and a small graphene flake with gold electrode contacts on the top; a gate voltage (Vg) is applied across the device to achieve optical modulation.
    An extremely small graphene-based free-space electroabsorption modulator has a low operating voltage of 1 to 3 V and low power consumption -- and it's CMOS-compatible.
    June 10, 2017
    (Courtesy of the University of Southampton)
    For erasable grating couplers fabricated on a photonic circuit (a) with length L and various taper widths W (b), transmission parameters vary as a function of taper length for different taper widths (c).
    To date, there are a few methods for testing integrated silicon photonics devices and circuits, but they all lack the possibility of comprehensive autonomous testing at the wafer...
    June 10, 2017
    The possible output wavelengths for a family of Raman fiber lasers pumped with either a Tm:silica fiber laser or an Er:ZBLAN laser are shown; the fibers are made of AsS, As2Se3, or TeO2. The ranges of efficient cascaded Raman wavelengths (1st through 6th) are shown in different colors. The bottom portion shows the use of both TeO2- and As2Se3-based lasers, with nested TeO2 fiber-based lasers followed by three orders of nested cascaded As2Se3 lasers (green rectangle at bottom right), yielding ultranarrow-linewidth wavelengths between 7 and 9.5 μm.
    Distributed-feedback Raman fiber lasers based on π-phase-shifted fiber Bragg gratings written in a glass fiber called a low-phonon-energy fiber have been developed.
    June 10, 2017
    Content Dam Lfw Print Articles 2017 06 1706lfw Nb3
    Data-detection algorithms for smartphones can capture data at a 4.5 kbit/s rate, and do it in conditions of low-enough light that it can be used as a nonline-of-sight (NLOS) system...
    June 10, 2017
    Content Dam Lfw Print Articles 2017 06 1706lfw Nb5
    Scientists at the Naval Research Laboratory have characterized the tunable refractive index of vanadium dioxide by measuring its optical transmittance and reflectance as a function...
    June 10, 2017
    Content Dam Lfw Print Articles 2017 06 1706lfw Nb4
    Deposition Sciences continues to advance its coating capabilities with its Spectral Metal and Sunshade coatings.
    June 10, 2017
    Content Dam Lfw Print Articles 2017 06 1706lfw Nb6
    A newly developed single-photon imaging lidar system uses a 10 mW eye-safe 1550 nm laser, indium gallium arsenide/indium phosphide SPAD detector, and algorithms specially designed...
    June 10, 2017
    Content Dam Lfw Print Articles 2017 06 1706lfw Nb2
    Fourth-generation fabrication processes produce aluminum aspheric mirrors up to 800 mm in diameter with surface figures as good as λ/100 (at 633 nm).
    June 10, 2017
    Content Dam Lfw Print Articles 2017 06 1706lfw Nb1
    A germanium nanowire photodetector for operation at a 1.55 μm wavelength with a diameter of only 20 nm integrated on a silicon substrate has been developed.
    June 10, 2017
    Conard Holton2
    Fortunately, engineers prefer acronyms to shorten the time they spend describing technologies. Without acronyms, we would be forced to refer to a certain large trade fair in Munich...
    June 10, 2017
    In October 2016, the FDA proposed designating green, blue, and other laser pointer colors as 'defective.'
    Pilot illumination is a serious safety concern because bright light can temporarily flashblind a pilot.
    May 26, 2017