QuantIC

Commercially available cameras have too many dark noise events to directly capture double-slit interference at the single photon level. However, in the research paper, “Video recording true single-photon double slit interference” (Aspden, R, Padgett, M and Spalding, G) published in the American Journal of Physics, QuantIC researchers use the detection of one photon in a time-correlated pair to herald the arrival of the partner photon at the camera. By activating the camera only when this partner photon is present, the camera noise levels can be significantly reduced. This system has enabled the improvement required for direct video imaging of Young’s double slit experiment with single photons.

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Following a beamsplitter, two collection arms can detect the correlated photons emerging from the BBO crystal. The signal-to-noise ratio is improved by using the heralding detector to only trigger the time-gated intensified CCD (ICCD) camera when a time-correlated photon is due to arrive.[/caption]

Reuben Aspden, lead author on the research publication and part of QuantIC’s Quantum Buddies Teacher Support network, is excited about how it could be used as a teaching tool for secondary school teachers on one of quantum physics’ key experiments. He said, “It’s the first full-field image of the double slit experiment using single photons, so it is possible to see the interference pattern appearing photon by photon and extends the simple double slit experiment done in the classroom into the truly quantum world, highlighting the weirdness of single photon interference.”

The full research paper and videos of the experiment can be downloaded here.

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First published: 13 September 2016