Quicker Than a Ray of Light

Researchers at M.I.T. have developed an imaging system capable of capturing 1 trillion frames per second. That is supposedly fast enough to catch the passage of a pulse of light.

The M.I.T. press release gives the good and bad:

The system relies on a recent technology called a streak camera, deployed in a totally unexpected way. The aperture of the streak camera is a narrow slit. Particles of light — photons — enter the camera through the slit and pass through an electric field that deflects them in a direction perpendicular to the slit. Because the electric field is changing very rapidly, it deflects late-arriving photons more than it does early-arriving ones.

The image produced by the camera is thus two-dimensional, but only one of the dimensions — the one corresponding to the direction of the slit — is spatial. The other dimension, corresponding to the degree of deflection, is time. The image thus represents the time of arrival of photons passing through a one-dimensional slice of space…

…But it’s a serious drawback in a video camera. To produce their super-slow-mo videos, Velten, Media Lab Associate Professor Ramesh Raskar and Moungi Bawendi, the Lester Wolfe Professor of Chemistry, must perform the same experiment — such as passing a light pulse through a bottle — over and over, continually repositioning the streak camera to gradually build up a two-dimensional image. Synchronizing the camera and the laser that generates the pulse, so that the timing of every exposure is the same, requires a battery of sophisticated optical equipment and exquisite mechanical control. It takes only a nanosecond — a billionth of a second — for light to scatter through a bottle, but it takes about an hour to collect all the data necessary for the final video. For that reason, Raskar calls the new system “the world’s slowest fastest camera.”

More information is available at the project website.

  • FO

    I was using streak cameras in… 2002? Oo
    And they were expensive but nowhere new things.

    Also, they are cheating.
    The build an image from many identical photons shooting in a very regular way, not of a single photon.

    This is still impressive and awesome, just the light passing through the plastic bottle is a marvel to behold.

    • Michael

      The alternative (imaging a single photon multiple times along its path) is impossible, because you cannot detect a photon without disturbing it substantially.

  • UrsaMinor

    Not to minimize the practical difficulties of getting the hardware and the software to play nice together, but this is very straightforward in concept. It is not any sort of breakthrough.

  • brian m

    Maybe that’s what Pinch used on chips when he saw the laser beam coming and ducked


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