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Thread: Interferometry

  1. #1 Interferometry 
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    Join Date
    Apr 2007
    In the circuitous haze of my mind
    How can I make an interferometer for under a thousand dollars? I am interested in doing a few experiments and tried to look for components....but the market is not very friendly towards people who do not have degrees in optics. I have the basic idea of how to make a crude one, but I actually would like to take measurements with this one.

    I was also thinking.....LIGO, their interferometer is very very long. I am assuming they built it that way so that the amount of effect per meter of the supposed gravitational waves will be increased. Say, a gravitational wave will change the length of a foot worth of pipe by 1cm. If you were to have 100 feet of this pipe, then wouldn't the total effect be 100cm? Having 100cm of effect as opposed to 1cm is better, right? I would think that you would be able to see a more potent interference pattern. Though....if you come from the perspective that it will be 1cm no matter what the length of the pipe, then I think the 1 foot pipe and therefore (in this case) the length of the path of the laser from the projection point to the mirror would be effected greater in proportion to the total length of the 100 foot pipe, and therefore cause a more powerful interference pattern. 1cm out of 1 foot, or 1cm out of 100 feet. The first one should work better....and actually, if you combine both perspectives, having a very long laser path would not help you much. Maybe I do not understand this well enough?

    Can you pass unpolarized light through an interferometer? I do not think it would matter considering your beam splitter should evenly divide the incoherent that possibly the incoherency would not matter? Is there a way to not dramatically alter the incoherent light and make it coherent?

    Is there a website that explains exactly how LIGO works? Considering that they are eating at our tax dollars (us americans, and no, america does not deserve to be capitalized in its current state), I think we deserve to know everything about their facilities and research. Now, I know we are paying the government to screw us over (CIA, NSA, FCC etc....), but I do not think that the scientific world is entirely detrimental to our existence yet.

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  3. #2  
    Moderator Moderator Dishmaster's Avatar
    Join Date
    Apr 2008
    Heidelberg, Germany
    Here are a few links that might help:

    I'd guess that especially the latter link could be useful. It is about SUSI, an optical interferometer based on small commercial optical telescopes. I think, you might find even more information on the web when looking for this project.

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