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  • Volume 56, Issue 08

    • Volume 56, Issue 08

    More content from Volume 56, Issue 08

    FIGURE 1. Raman spectra of common biological molecules: cholesterol, triolene, acitin, DNA, oleic acid, collagen (type 1), glycogen, and lycopene.
    Low-power, nondestructive medical laser applications will help shape the future of photonics in healthcare.
    Aug. 11, 2020
    FIGURE 1. A new, low-cost bidirectional optical subassembly (BOSA) uses a single glass-sealed conventional TO-can package and incorporates optical transmitting and receiving functions into a silicon optical bench.
    The high-volume, high-mix nature of new TO-can packages for high-speed DCI and 5G wireless network rollouts require ±1~2 µm machine accuracy and flexibility to quickly handle ...
    Aug. 11, 2020
    FIGURE 1. The leaf blend grade verification system consists of an enclosure, tungsten halogen lamps, a cooling fan, and a hyperspectral camera.
    Based on factors such as growing location, weather, leaf position on the plant, color, and texture, tobacco is divided into grades, a process previously done by manual inspection...
    Aug. 11, 2020
    The LambdaVision artificial retina generates an ion gradient from ordered layers of bacteriorhodopsin to restore useful sight when implanted in place of irretrievably damaged photoreceptors in the eye.
    An artificial retinal implant based on the photosensitive molecule bacteriorhodopsin can potentially reach higher resolutions than conventional semiconductor-based retinal implants...
    Aug. 11, 2020
    Absorption (1 - reflectivity R) spectra of plasma-patterned (a) and conventionally etched (b) AZO metasurfaces show several spectral bands; notable is the similarity in spectral absorption for the two different surfaces. Different colors correspond to different metasurface feature sizes: red is 650 nm, green is 850 nm, dark blue is 1050 nm, and violet is 1250 nm. The solid black line is the absorption of a planar AZO film with no patterning.
    Rather than etching a metasurface layer that could cause problems for further layers, plasma patterning leaves the metasurface layer flat.
    Aug. 11, 2020
    An optical fiber or waveguide has segments that alternate between normal and anomalous dispersions (NA and AD; a); this allows supercontinuum generation to occur with the deleterious effects of dispersion minimized. A plot of normalized energy density spectrum versus propagation for a supercontinuum-generating fiber with alternating dispersion (b) shows that the spectral broadening keeps increasing with length and is not limited by dispersion. A plot of intensity and shape of the pulse vs. propagation length (c) shows that the undesired pulse stretching in the ND fiber segments is compensated by the AD segments.
    An optical fiber or waveguide with segments of alternate-signed dispersion eliminates stagnation of spectral broadening due to dispersion effects.
    Aug. 11, 2020
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    A variable-period diffraction grating actively steers a terahertz beam by compressing the grating to various degrees; the device can be driven by a speaker for fast beam-steering...
    Aug. 11, 2020
    Scientists at Fermilab studied optically clear cements for use in scintillator optics; tests under ionizing radiation from their accelerator produced a clear winner.
    Aug. 11, 2020
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    A spatial light modulator for laser processing of carbon-fiber-reinforced plastics and low-dielectric-constant materials has improved dielectric films that boost its power-handling...
    Aug. 11, 2020
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    The use of silicon in regular nanophotonic arrays can boost light emission from associated organic molecules by 20-fold.
    Aug. 11, 2020
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    Near-infrared Raman spectroscopy, photonics in healthcare, industrialized scientific ultrafast lasers, and waveguide optics are just a sampling of what's featured in the August...
    Aug. 11, 2020
    (Image credit: Johns Hopkins University; adapted from M. Graham et al. [1]))
    This catheter contains a 1-mm-diameter optical fiber that pipes laser pulses at a 750 nm wavelength to the heart region to perform photoacoustic imaging. The pulses each have an energy of 2.98 mJ at the fiber tip; repetition rate is 600 Hz.
    An optical fiber in a cardiac catheter produces photoacoustic signals at the tip of the catheter; robotic vision guides the catheter.
    April 17, 2020