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  • Volume 57, Issue 04

    • Volume 57, Issue 04

    FIGURE 1. Schematic of a typical ultrafast fiber-laser oscillator (a); Calmar Laser’s palm-sized Mendocino ultrafast fiber laser offers output wavelengths from 780 to 1560 nm (b).
    Lasers & Sources

    Compact ultrafast fiber lasers enable applications in new spaces

    Tony Lin
    April 21, 2021
    Fiber-based ultrafast laser platforms enable medical and industrial applications from cancer diagnosis to terahertz imaging and 3D nanoprinting.
    FIGURE 1. Lasers commonly used for fractional photothermolysis treatment have wavelengths highly absorbed by water and less absorbed by melanin and hemoglobin.
    Bio&Life Sciences

    1470 nm diode lasers enable home skin rejuvenation

    Kevin Yang
    April 21, 2021
    As a monolithic semiconductor device that converts electrical energy directly into light, the diode laser, when compared with other laser sources for skin rejuvenation, has many...
    FIGURE 1. Automotive HUD system concept.
    Optics

    Designing and analyzing automotive head-up displays

    Chihyun Chan
    April 21, 2021
    Design of head-up display systems for automotive applications benefits from modern optical design and illumination software.
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    Fiber Optics

    Lensed photonic-crystal fibers have long working distances

    John Wallace
    April 21, 2021
    A method of fusing photonic-crystal fiber ends using a heated U-shaped graphite filament produces lensed tips with long working distance and wide bandwidth.
    FIGURE 1. Attenuation of optical fibers made of fluoride glasses, showing a significantly wider transmission window into the mid-IR as compared to silica fibers. Indium fluoride (InF3) glass has a wider transmission window in the mid-IR than zirconium fluoride (ZrF4) glass.
    Lasers & Sources

    Mid-IR supercontinuum laser covers key spectral bands for spectroscopy

    Reza Salem
    April 21, 2021
    A commercially available mid-IR supercontinuum source has a broadband output from 1.3 to 4.5 μm, providing orders-of-magnitude higher brightness than thermal IR sources.

    More content from Volume 57, Issue 04

    FIGURE 1. Two-dimensional array of micromirrors with three possible angular positions: flat, tilted v degrees anticlockwise, and tilted +v degrees clockwise.
    Test & Measurement

    Advances in DMD-based spectrometers benefit industry and medicine

    Thomas Rasmussen
    April 21, 2021
    Compact near-infrared spectrometers based on digital micromirror devices (DMDs) can be lower in cost than diode-array spectrometers while maintaining high stability.
    FIGURE 1. Schematic of an edge coupler (a) and a grating coupler (b).
    Optics

    Silicon photonics gets a boost from low-profile, monolithic optical input/output coupler

    Tiina Delmonte
    April 21, 2021
    Efficiently linking optical fibers to silicon photonics is crucial to high-volume deployment; a new monolithic 1:1 imaging coupler is compact and suitable for volume fabrication...
    (Courtesy of the Catalan Institute of Nanoscience and Nanotechnology)
    A new interferometric sensor has demonstrated the ability to rapidly and accurately detect low levels of pathogenic bacteria in a compact point-of-care device.
    Optics

    Micro-interferometer speeds detection of dangerous pathogens

    Richard Gaughan
    April 21, 2021
    A bimodal waveguide sensor has a waveguide portion biochemically functionalized to bind to a specific target, allowing interferometric sensing of the target.
    (Adapted from J. Knall et al. [1])
    A Yb-doped silica fiber is pumped with light at a wavelength ranging from 1020 to 1070 nm, causing anti-Stokes fluorescence that carries some energy away. Depending on the wavelength, enough energy can be carried away to exceed the amount of energy dumped into the fiber as heat, thus cooling the fiber. As can be seen, the optimum pump wavelength in the experiment was about 1040 nm.
    Lasers & Sources

    Self-cooled silica fiber laser exceeds the athermal point

    John Wallace
    April 21, 2021
    A ytterbium-doped silica fiber laser pumped with light at 1040 nm loses enough heat via anti-Stokes fluorescence to become athermal.
    (Image credit: SIOM)
    For extreme-ultraviolet (EUV) lithographic systems in which the photomask needs to be optimized to minimize optical-proximity effects, a simultaneous source-mask optimization (SMO) algorithm using a thick-mask model results in more-accurate features printed at the wafer.
    Software & Accessories

    Source-mask optimization using thick masks improves EUV lithography

    John Wallace
    April 21, 2021
    A software algorithm based on social learning particle swarm optimization (SL-PSO) simultaneously optimizes source and mask for extreme-ultraviolet (EUV) lithography.
    A resonance curve from two coupled microring resonators producing a microcomb is fit with a curve that models a resonance doublet.
    Optics

    Two coupled microring resonators produce an efficient, spectrally flat microcomb

    John Wallace
    April 21, 2021
    Using a laser with a milliwatts-level output, two linearly coupled microresonators produce a microcomb potentially widely useful in spectroscopy, communications, and other applications...
    In a single-mode optical fiber with a 10-μm-diameter core, a high-refractive-index rod is placed a distance S away in the cladding; the rod itself supports a mode, in addition to the mode supported by the core (a). The idea is for the rod to couple resonantly to the core, drawing light in certain spectral regions away from the core and absorbing it, thus serving as a spectral filter. The width of the peak bandwidth narrowed as the rod was moved farther from the core (b).
    Fiber Optics

    Single-mode fiber with absorbing rod serves as spectral filter

    John Wallace
    April 21, 2021
    A single-mode silica fiber has a high-refractive-index rod placed in the cladding that resonates with the core, absorbing light at certain wavelengths.
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    Optics

    When light reflects from a multilayer dielectric, how deep does it go?

    John Wallace
    April 21, 2021
    Confirmed by experiment, calculations show how deep light goes into a DBR mirror before it reflects; this is relevant for determining microcavity lengths.
    (Image credit: Andrea Toulouse, Johannes Drozella, Simon Thiele, Harald Giessen, and Alois Herkommer)
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    Test & Measurement

    3D-printed spectrometer has a 100 × 100 square micron footprint

    John Wallace
    April 21, 2021
    A 3D-printed miniature spectrometer is so small that it can fit on the tip of an endoscope or on a miniature image sensor.
    (Courtesy of NASA)
    The global geologic map of Mars published by the U.S. Geological Survey in 2014; it combines information from four orbiting spacecraft that have been acquiring data for more than 16 years.
    Executive Forum

    The new Martian chronicles

    Conard Holton
    April 21, 2021
    The current missions to Mars are exciting to follow, and show the value of science and photonics as exploration and the search for life on another world put life on Earth in perspective...
    2104 Lfw Ils Sch 1
    Industrial Laser Solutions

    Applications for ultrashort-pulse laser surface processing

    Ron Schaeffer
    April 21, 2021
    Technology advances now allow very fast delivery of high-repetition-rate, ultrashort-pulse light to large functional surfaces.
    2104 Lfw Ils Reh 1
    Industrial Laser Solutions

    3D printing improves strain gauge sensor manufacturing

    Matthias Rehberger
    April 21, 2021
    Digital printing and laser processes replace the manual process steps of conventional bonding.
    New Image 2
    Industrial Laser Solutions

    New normals

    David Belforte
    April 21, 2021
    It’s been a bit more than 12 months since U.S. cities began to shut down in response to the spreading COVID-19 virus.
    (Photo 183113861 © Toodlingstudio | Dreamstime.com)
    Dreamstime M 183113861
    Commentary

    Will laser markets bounce back from COVID-19?

    John Lewis
    April 2, 2021
    They likely will—find out how by viewing the Lasers & Photonics Marketplace Seminar Wrap Up Roundtable Discussion.