Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

A few double slit experiments.

  1. Aug 17, 2012 #1
    Hello
    Lets make a few double slit experiments.
    Lets say we have water pond with a set of point size emitters on the left
    and a set of independent wave energy detectors on the right side.
    http://img560.imageshack.us/img560/571/slits1.png [Broken]

    Now let each point emitter emits wave but with big time intervals between each other.
    So we will have like many double slit experiments executed one by one.

    After all points finish emitting lets look how much total energy was detected by each detector separately. There it is easy to see that all detectors will measure almost the same amount of total energy.

    Now lets repeat experiment so that all points emits simultaneously.
    We will have total wave similar to this
    http://img339.imageshack.us/img339/1625/slits2.png [Broken]

    which will cross 2 slits and will make interference pattern on the detectors.
    So some detectors will measure much more energy than other.

    Am I right?

    Now the question: can we obtain the same scenario for light and how?
     
    Last edited by a moderator: May 6, 2017
  2. jcsd
  3. Aug 17, 2012 #2

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    Right.

    Take a laser with a very narrow slit as source, move it during the experiment.
    Now remove the very narrow slit and fix the laser at a specific position.
     
  4. Aug 18, 2012 #3
    Yes it would work, but you are using flat wave which already exist in space.
    See left picture:
    http://img841.imageshack.us/img841/2163/slits3.png [Broken]

    But I would like to make things in reverse, to make flat wave from real point sources
    like you see on right side.
    For example by using exactly equal length light fibers.

    Now if we will use a weak laser with not enough photons we will have situation similar to the first situation with water.

    But if we will use much more photons maybe we can obtain situation like Nr 2 with water ?
     
    Last edited by a moderator: May 6, 2017
  5. Aug 18, 2012 #4

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    You can use a diffraction grating and a distant laser to get many point-like sources in phase ;).

    Intensity does not matter, you can do interference experiments with single photons.
     
  6. Aug 18, 2012 #5
    Yes, I well understand what you mean.
    But there things are not so simple.
    If you send a single photon a small bit of surface of diffraction grating will not be like point source.
    Only order 0 and maybe a few more (up to grating).
    But it will not look like point source at all.

    At my scheme the end of a single fiber can be seen as real light point, because it can emit to all directions.
    Now you could check what happens if you use diffraction grating like initial source.
    This will be full analogy of water Nr2 version, but my with fibers and weak laser will be like Nr1 water version.
     
  7. Aug 19, 2012 #6
    Instead of a big set of light fibers, which is unrealistic to produce,
    I suppose much easier would be to use some fat plate with micro holes in it.
    Helpfully laser drilling technologies allow to do it.
    http://www.oxfordlasers.com/micromachining/applications/laser_drilling?gclid=COnhv8L28rECFagmtAodIiwA7w [Broken]

    Thickness of the plate could be so that we avoid single photon's interference with itself.

    This thickness also would show how long individual photon's probability wave can be.

    Likely would be better to use longer waves, for example far infrared 0.1 mm
    Because of easier to produce holes and because we may obtain much bigger number
    of photons with the same laser power.

    For this phenomenon likely will be important how much photons we have inside cubic of space of size of 1 wavelength. Because we excluded photon's interference with itself we need enough photons to make interference again, so that photons (their probability waves) can touch each other.
    For far infrared it is much easier to reach many thousands of photons inside wavelength size cubic.
    For visible light it is harder to reach even 1 photon inside mentioned wave cubic.

    But still the question is how many photons is needed to get interference back
    by analogy to water wave experiment Nr2 ?
     
    Last edited by a moderator: May 6, 2017
  8. Aug 19, 2012 #7

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    With a usual fiber, it will not.
    Make your slits in the diffraction grating similar to the wavelength of light. The intensity will be bad, but if you need a point-like source...
    There are other nearly point-like sources, but keeping the different points in phase is the tricky thing.


    Why did you exclude this? And why do you think a higher photon density will change anything?
     
  9. Aug 19, 2012 #8
    Ok we may exclude technical questions how to produce such good quality emitter.
    Just lets say we already have such flat surface/emitter where all points emits randomly to all/random directions.
    But lets all photons are synchronized by phase, so each point which currently emits,
    do it with the same phase at any point of the surface.
    But as I mentioned before the directions are random.

    If we have very small number of photons we have the same situation to water wave experiment Nr1
    If we have very big number of photons we have the same situation to water wave experiment Nr2

    If we have very big number we may say any single point of such surface emits to all directions simultaneously.
    So we have classical 1 point emitter at any point of the surface. And so the whole surface would produce flat wave like with water Nr2

    Here is another picture I was painted yesterday for separate ends of optical fibers.
    http://img854.imageshack.us/img854/1308/slits4.png [Broken]
    The same can be applied to points of such ideal surface.
     
    Last edited by a moderator: May 6, 2017
  10. Aug 19, 2012 #9

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    Ah. Well, that depends on the source. If you use the laser + diffraction grating setup, photon density does not matter. If you really use independent sources which might or might not emit photons, you need a high intensity. I wonder how such a setup would look like.
     
  11. Aug 19, 2012 #10
    The things I already was described is just an introduction to the next double split experiment.
    For the next double slit experiment it is enough to know that with far infrared laser we can reach necessary photons' density to obtain interference in a way of water wave experiment Nr2.

    Lets go to the setup with water. And lets allow water to move with velocity v.

    It is easy to show that at the first experiment (Nr1) we will not obtain any measurable consequence.

    For second (Nr2) water wave experiment we will also obtain flat wave which is parallel to the surface of source.
    But when such flat wave reach diffraction grating it will produce a bit different interference.
    Diffraction pattern will be shifted by angle v/w (when v<<w) Where w velocity of water wave.

    Here is animation done not by me, but still well suitable for this case.
    http://img822.imageshack.us/img822/3416/slits.gif [Broken]
    Here two slits are assumed at the bottom of the picture
    and water or ether wind moves from the left to the right.

    So this experiment is very well sensitive (first order effect) to water flow.
    Now we can reproduce the same experiment with far infrared laser to measure ether wind.
    This is the most cheapest experiment with can detect ether wind and
    together it can not be nullified by possible hard body contraction (in LET style and another mentioned by me at an other tread).
     
    Last edited by a moderator: May 6, 2017
  12. Aug 19, 2012 #11

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    Oh come on, not this again...
    *unsubscribe*

    Your ether would/could influence the condition of phase correlation, too.
     
  13. Aug 19, 2012 #12
    Yes this one cames from analysis of previous, but is very different.
    It is just a tool, not a theory (just some why far infrared).
    For people who has far infrared laser it will takes just a half an hour to test all
    possible directions, especially vertical.

    I am not so clear what do you mean by: condition of phase correlation.
    At what place?
     
  14. Aug 20, 2012 #13
    At the moment I am not so clear how happens/generates phase synchronization inside a laser itself.
    I mean phase synchronization between separate horizontal light beams which are running back and force between two mirrors.
    At the left we have bended wavefront inside a laser.
    Who makes them synchronized like on the right side?
    http://img94.imageshack.us/img94/4220/wavefront.png [Broken]

    Even if I am wrong with this setup it only shows how hard it is to find real experiment sensitive to ether wind when you honestly try to account all possible factors.
     
    Last edited by a moderator: May 6, 2017
  15. Aug 20, 2012 #14

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member

    This "ether wind" clearly fascinates you. Unfortunately you seem intent on following your own course to invent experiments to detect / measure it. How, in detail, are your ideas any different from MMX and why should you think you could be the one to revolutionise Physics (and so easily)? You can't expect to jump into this half way through and to get anywhere, I'm afraid. A few year's worth of hard graft on the basics is needed first (as all the other 'revolutionisers' have shown).
    Your diagrams are just the same sort of thing as you'd find in any basic theory on diffraction but you omit the essential maths.
     
  16. Aug 20, 2012 #15
    MMX and all family made from it is not sensitive if you would consider LET's (or my) type of contraction.
    Experiments usually are based on simple enough maths but complicated set of many different factors.
    When I account all factors your experiments becomes not sensitive to the main thing they was designed for. So for any inventor it becomes very interesting to try to find right setup.
    Two simple, but very expensive setups was found, but still it is interesting to find something cheaper.
    Also it is interesting to show that current known setups are really not sensitive because people do not spend enough time to think about all factors.
    I does not started with it it yesterday, and not even 10 years ago. I have started with it when I was a kid and it was much more time ago...

    But still how about light wavefront synchronization inside laser?
    What do I am missing here, how different layers of light becomes synchronized ?
    (at my previous post)
     
  17. Aug 20, 2012 #16

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member

    As you have not included any Maths / Quantitative discussion then you cannot assert anything about sensitivity. Without that, you are wasting your time. What factors have you considered (in detail) that haven't been considered already?
     
  18. Aug 20, 2012 #17
    Most likes to say: Lorenz's contraction is ad-hoc.
    But he had its own explanation of his hypothesis.
    Hoverer anybody with technical thinking constancy of size would name like ad-hoc.
    How can size of hard body stay the same if we assumer moving aether
    relative to which all electromagnetic interaction occurs/spreads.
    This directly could effect size of hard bodies.
    If we assume ether than constant size is pure ad-hoc.
    These two ideas: ether and constant size contradict to each other so can not be used together.
    So if you make experiment like MMX you can not exclude contraction.
    And everybody knows that in this way MMX becomes not sensitive to what it was designed.

    Here is just motivation why we need another experiments.
    Are my setups good enough it is another question.
    Anyway somebody will make some experiments, so why not to set up a prize for 1000 000 $
    for an idea of experiment which would show problems inside current theory?
    This would accelerate progress a lot, because nobody can find good experiment by being inside one theory, and nobody can create full new theory alone.
     
  19. Aug 20, 2012 #18

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member

    If you were to put up a million dollars then I'm sure you would find someone to take it from you. If not, you will need to support your ideas with ACTUAL NUMBERS and not just arm waving. You need to talk Science and not fantasy.
     
  20. Aug 20, 2012 #19
    Yes likely, but if such situation with prize would came true it is real chance that more than one man with excellent Maths education would find me and would offer 50% for collaboration.

    Also (if not touch me), this would really refresh public thinking.
    Many of them who now spend money in Las Vegas would find better hobby to learn physics,
    to talk about it with friends and so on. IQ would double for many of them :)
    Funny, but this is much realistic.

    Also this can be used for solving many other problems.
    Here is not so big problems with copyright, just make some site where people can register their ideas. So it can take a few minutes from generating to registering.

    About Maths. When Einstein found his E = m0*c^2 (inner energy of mass)
    he made assumption that photon have mass p/c .
    And this assumption was named like genial at many textbooks.
    The same way (by doing the same assumption for photon's mass like p/c)
    I have derived analogy of relativistic mass and relativistic kinetic energy for ether.
    But people was not happy (at another forum) with this assumption.
    This is strange.
    And what about my assumption that hard bodies can be seen like standing waves.
    Even if (maybe) Einstein's assumption about mass of photon was not correct enough, he had obtained right results for E_inner = m0*c^2
    So the same way amount of contraction can be correct even if hard bodies are not exactly like standing waves.
     
    Last edited: Aug 20, 2012
  21. Aug 20, 2012 #20
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: A few double slit experiments.
  1. Double Slit Experiment (Replies: 4)

Loading...