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I Birgit Dopfer interference experiment

  1. May 8, 2016 #1
    Hello. I'm interested in the experimental details of the above and have found what I believe to be the original published write up of the experiment. The document is in German and I have managed to get a reasonable understanding of the details mainly from the diagrams and graphs. Translation is proving to be a bit of a task and I hope someone can help me with the following two words related to a Heissenberg lens:

    Brennebene: The google translation of this word is "burning plane" and I assume this means the focal plane of the lens. If so it seems to make sense.

    Linsenbrennebene: The google translation of this word is "lens burning plane" and according to my understanding so far this would seem to make sense if the plane was at a distance of 2f in other words twice the focal length from the lens. The problem is that some of the results plotted refer to a distance of f and not 2f, for example the title of the first graph of a particular set is as follows

    Heisenberg Detector D1 in der Linsenbrennebene, f

    I would be grateful if anyone can clarify this .
    Thank you.
  2. jcsd
  3. May 8, 2016 #2


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    The plane which is perpendicular in the focus to the axis is called Brennebene (sometimes Fourier plane, focal plane or focal surface). The additional "Linsen" just means lens.
    You often can do the following trick: go to the German version of Wiki, type in the word, and then change to the English version. (They are usually different but the figures and combined explanations often help.)
  4. May 9, 2016 #3


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  5. May 9, 2016 #4
    https://www.physicsforums.com/https:users./iu.se/jalar/kursor/QF/assignments/Dopfer1998.pdf [Broken]
    Thank you fresh 42 and vanhees71. The thing that I'm stuck on refers to the three sets of results on the following pages;
    I think these refer to the experiments shown schematically on pages 36-38. In all three sets of results the distance of D2 increases. The first two sets of results are similar except for separations equal to and close to 2f. From what I guess so far, in the first set of results it is D2 that is scanned and in the second and third set it is D1 that is scanned. I can probably confirm this or otherwise by continuing with the translation.
    It is the third set of results I find most confusing at the moment. For the smallest separation D1 is in "der linsenbrennebene, f". Now if D1 is in the focal plane I would expect to see an interference pattern and not the apparently overlapping diffraction patterns. Also I would have thought that diffraction patterns would be observed for a separation 2f and not f. To add to my confusion, the patterns for separations at or close to 2f are similar for sets of results two and three.
    Yikes, Iguess i need to get more busy with translation. However, it doesn't help when you see words such as brennebene and linsenbrennebene. It seems that they are different but since they are both labelled with an apparently equal inititial separation of f on the graphs it seems they are the same.
    Thanks again.
    Last edited by a moderator: May 7, 2017
  6. May 9, 2016 #5


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    I don't have any clue about the topic. But if you need assistance with the translation you're welcome.
    Edit: my ignorance could be even an advantage for I won't guide you in the wrong direction :wink:
    Edt2: your link doesn't work here, are there any other sources?
    Last edited: May 9, 2016
  7. May 9, 2016 #6
    Thanks for the offer fresh 42 but when you look at the document you will see it's an enormous task. I will do it myself and muddle through but might come back with the odd word that confuses me. I don't know what's wrong with the link but you might get access to the document by googling the following:

    Zwei Experimente zur Interferenz von Zwei-Photonen Zustanden
    Last edited: May 9, 2016
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