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    • Volume 56, Issue 01

    More content from Volume 56, Issue 01

    (Image credit: MBI)
    A full characterization of 10 fs near-infrared (near-IR) pulses produced by a high-average-power few-cycle laser system is done using a dispersion scan measurement. First, the spectral phase of the pulses is varied (chirping) by inserting glass with gradually increasing thickness into the beam. Then, in a thin nonlinear crystal, the second harmonic of the chirped pulses is generated and its spectrum recorded for the series of different glass insertions. In this way, a 2D trace is recorded (a), from which the missing phase information can be extracted by using an iterative numerical algorithm. The simulated trace given by the phase-retrieval algorithm is shown in (b), exhibiting a striking similarity with the measured trace. The measured spectrum of the pulse together with the retrieved phase are shown in (c), while their Fourier transform, giving the pulse shape (red curve), is displayed in (d). The black curve in this panel corresponds to the shortest possible pulse for the measured spectrum.
    A ytterbium-fiber chirped-pulse amplifier and thirtyfold compression by a gas-filled hollow-core fiber generate three-optical-cycle (10 fs) pulses, adding up to 318 W average ...
    Jan. 28, 2020
    FIGURE 1. A test dataset for hazy images consists of a city view (a), a turbid underwater view (b), and a forest scene (c).
    Image dehazing can improve the visual quality of images for computer-aided applications and human interpretation.
    Jan. 28, 2020
    FIGURE 1. Scanning time-of-flight lidar uses a laser as a light source.
    Will single-photon avalanche photodiodes become the standard in time-of-flight lidar photodetection?
    Jan. 28, 2020
    Coupling discrete LEDs to individual fibers (which are then bundled together) creates a multicolor output that can be spatially homogenized with very low loss with help from an integrating rod; this 15-emitter prototype is a precursor to FiberTech Optica’s current 18-emitter light engine.
    Coupled with fiber optics, LEDs provide flexibility for a variety of bioimaging applications.
    Jan. 28, 2020
    FIGURE 1. Raman spectra of lipid-rich fat tissue (orange) and protein-rich muscle tissue (purple); the broadband, autofluorescence background is clearly visible in both spectra, each of which was collected using a similar acquisition time.
    New CCDs deliver 2–7X higher sensitivity in the wavelength range relevant for bio-Raman measurements and allow greater detection limits or shorter experiment times.
    Jan. 28, 2020
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    The Wassenaar Arrangement results in controls on exports that have many implications for global lasers and photonics manufacturers.
    Jan. 28, 2020
    (Courtesy of Photoneo)
    FIGURE 1. A PhoXi 3D Scanner by Photoneo mounted on a robot arm automates bin picking, depalletization, and other industrial applications using Photoneo automation systems.
    Technical advances have led to small and easily configurable 3D imagers for industrial use.
    Jan. 28, 2020
    FIGURE 1. Typical light-current-voltage (LIV) curve for a 940 nm VCSEL array shows VCSEL power-conversion efficiency of 45%.
    Promising developments in VCSEL technology, including power-conversion efficiency, single-mode beams, and flip-chip-mounted designs, may be significant factors enabling next-generation...
    Jan. 28, 2020
    (Image credit: NTU Singapore)
    The amplified spontaneous emission (ASE) threshold is plotted for both a simulation and experimental results (a), showing good agreement; the CQD film photoluminesces at about 640 nm (b).
    Applying a sinusoidal electrical bias to colloidal quantum dots (CQDs) lowers their amplified spontaneous emission (ASE) threshold, potentially enabling electrical pumping of ...
    Jan. 28, 2020
    An aluminum nitride (AlN) piezoelectric nanoplate suspended by two anchor beams is driven by two interdigitated electrodes (IDEs) so that it resonates; IR radiation received by the device changes the resonance frequency, providing a measurement of the IR flux received by the nanoplate.
    The resonance frequency of a piezoelectrically driven aluminum nitride nanoplate changes as a function of IR radiation absorbed by the detector.
    Jan. 28, 2020
    The magnitude of various Zernike coefficients, here shown as Noll indices ranging from 2 to 28, are compared for the inputs (black) and outputs (blue) of test PSFs analyzed by a deep residual neural network. It can be seen that the input and output Zernikes closely agree.
    Given the 2D intensity profile of a point-spread function (PSF) at 5 different focal positions, a deep residual neural network accurately determines the Zernike coefficients for...
    Jan. 28, 2020
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    Editor in Chief John Lewis invites you to enjoy Laser Focus World's January 2020 issue, which includes trends in photonics technologies, applications, and markets, along with ...
    Jan. 28, 2020
    An all-inorganic silicon white-light LED has an EQE of 1.0%; driving the device at higher voltages shifts the spectrum’s center wavelength toward the blue.
    Extracting light from silicon to make an LED is difficult, but researchers have created a white-light silicon LED with good efficiency for a first prototype.
    Jan. 28, 2020
    Structured illumination microscopy (SIM) provides spatial superresolution through analysis of the Moire pattern that results when two frequencies overlap (a). SIM expands the spatial reciprocal domain (b), while pSIM expands both the spatial and angular reciprocal domains (c).
    A new technique allows standard commercial structured illumination microscopy (SIM) systems to achieve superresolution polarization imaging.
    Jan. 28, 2020
    After synthesizing a small molecule that emits near 1100 nm, a Stanford-Wuhan University team increased its quantum yield by binding it to albumin. The dye complex has shown its ability to monitor both normal and abnormal circulatory flow.
    A biocompatible organic small-molecule dye with improved quantum yield allows improved imaging in the low-attenuation, low-scatter NIR-II band.
    Jan. 28, 2020
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    Using a SPAD to count photons from various types of light sources shows that all the sources had similar spectral behavior for low-frequency fluctuations.
    Jan. 28, 2020
    Photo credit: NTU Singapore
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    A silicon-photonic chip operating at a 1550 nm wavelength generates the quantum coherent states needed for uncrackable quantum-cryptographic transmission of information.
    Jan. 28, 2020
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    The high powers and relevant optical frequencies of an x-ray FEL could help hydrogen isotope nuclei to overcome Coulomb repulsion and achieve fusion.
    Jan. 28, 2020
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    Cellulose-based fiber-optic sensors are capable of absorbing and releasing water or other substances, enabling them to be measured.
    Jan. 28, 2020
    An optical quality-control system including transmitted fringe deflectometry, dark-field illumination, and light transmission characterizes defects in small, highly curved lenses...
    Jan. 28, 2020
    FIGURE 1. A sizable crowd assembles as they await the opening of the 2019 SPIE Photonics West exhibition.
    We can’t predict the future, but at SPIE Photonics West 2020, you can learn all about the laser, optics, and photonics technologies shaping it.
    Jan. 6, 2020