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Sample Experiments – Quantum Eraser

We set up the quED and the Michelson Interferometer add-on quED-MI as usual:

We start with the Single Photon Interference effect as before:

quED MI Screenshot Interference

The quED-MI is designed in such a way that the polarisation of the photons at the input of the interferometer is diagonal (i.e. 45° between horizontal and vertical). Now we add polarisers in the two arms of the interferometer, one horizontal, one vertical. This affects the interference:

This can be interpreted in the following way: At the output of the interferometer, you can determine by the polarisation of the photon, which of the two possible paths it has taken (so-called “which-way” or “welcher-Weg” information). Thus, the interference is destroyed.

Now, we add a third polariser at the output of the interferometer. This is what happens:

The interference re-appears. Do you know why it is called the “quantum eraser”?

What do you need?

  • 1 x quED (high rate version advised)
  • 1 x quED-MI (for optimal resolution use motorised version)

The three polarisers are integrated into the quED-MI, you can swing them in and out.

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