• Turning any camera into a polarization c

    From ScienceDaily@1:317/3 to All on Fri Mar 18 22:30:36 2022
    Turning any camera into a polarization camera
    Metasurface attachment can be used with almost any optical system, from machine vision cameras to telescopes

    Date:
    March 18, 2022
    Source:
    Harvard John A. Paulson School of Engineering and Applied Sciences
    Summary:
    Researchers have developed a metasurface attachment that can turn
    just about any camera or imaging system, even off-the-shelf systems,
    into polarization cameras. The attachment uses a metasurface of
    subwavelength nanopillars to direct light based on its polarization
    and compiles an image that captures polarization at every pixel.



    FULL STORY ========================================================================== Polarization, the direction in which light vibrates, provides a lot of information about the objects with which it interacts, from aerosols
    in the atmosphere to the magnetic field of stars. However, because this
    quality of light is invisible to human eyes, researchers and engineers
    have relied on specialized, expensive, and bulky cameras to capture
    it. Until now.


    ========================================================================== Researchers from the Harvard John A. Paulson School of Engineering and
    Applied Sciences (SEAS) have developed a metasurface attachment that
    can turn just about any camera or imaging system, even off-the-shelf
    systems, into polarization cameras. The attachment uses a metasurface
    of subwavelength nanopillars to direct light based on its polarization
    and compiles an image that captures polarization at every pixel.

    The research is published in Optics Express.

    "The addition of polarization sensitivity to practically any camera will
    reveal details and features that ordinary cameras can't see, benefiting
    a wide range of applications from face recognition and self-driving cars
    to remote sensing and machine vision, "said Federico Capasso, the Robert
    L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research
    Fellow in Electrical Engineering at SEAS and senior author of the study.

    In 2019, Capasso and his team developed a compact, portable camera
    that used a metasurface to image polarization in a single shot. In
    this research, the team explored how to generalize the concept of a polarization camera.

    "After building the specialized polarization camera, we wanted to go more
    in depth and investigate the design rules and trade-offs that govern
    pairing a special polarization component with a conventional camera
    system," said Noah Rubin, a graduate student at SEAS and co-first author
    of the study.

    To demonstrate those design rules, the researchers attached the
    polarization metasurface to an off-the-shelf machine vision camera,
    simply screwing it on in front of the objective lens, in a small tube
    that also housed a color filter and field stop. From there, all they
    needed to do was point and click to get polarization information.

    The nanopillars direct light based on polarization, which forms four
    images, each showing a different aspect of the polarization. The images
    are then put together, giving a full snapshot of polarization at every
    pixel.

    The attachment could be used to improve machine vision in vehicles or
    in biometric sensors for security applications.

    "This metasurface attachment is incredibly versatile," said Paul
    Chevalier, a postdoctoral research fellow at SEAS and co-first author of
    the study. "It is a component that could live in a variety of optical
    systems, from room-size telescopes to tiny spy cameras, expanding the application space for polarization cameras." The research was co-authored
    by Michael Juhl, Michele Tamagnone and Russell Chipman. It was supported
    by the Earth Science Technology Office (ESTO) of the National Aeronautics
    and Space Administration (NASA) and by the U.S. Air Force Office of
    Scientific Research under grant no. FA9550-18-P-0024. It was performed in
    part at the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Coordinated Infrastructure (NNCI), which is supported by
    the National Science Foundation under NSF award no. 1541959.


    ========================================================================== Story Source: Materials provided by Harvard_John_A._Paulson_School_of_Engineering_and_Applied
    Sciences. Original written by Leah Burrows. Note: Content may be edited
    for style and length.


    ========================================================================== Journal Reference:
    1. Noah A. Rubin, Paul Chevalier, Michael Juhl, Michele Tamagnone,
    Russell
    Chipman, Federico Capasso. Imaging polarimetry through metasurface
    polarization gratings. Optics Express, 2022; 30 (6): 9389 DOI:
    10.1364/ OE.450941 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/03/220318104923.htm

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