I am planning to do a project in which I plan to mimic the LISA interferometer. For this I use the fabric material, Lycra to mimic space time and use spherical balls, forming a couple and connected to a rotating shaft thus mimicking binary stars.

As the balls rotate, they would cause waves in the fabric. Further away from the binary system is the triangular interferometer, this system comprises of three discs, each having a laser and a sensor. When the laser in aligned with the second discs' sensor, and the laser of the second to the third's sensor and lastly the third's laser to the primary's sensor, the three form a equilateral triangular system.

The three discs would be placed on individual corks and each disc would be connected to a vertical shaft with a shock absorber( so that the disc can oscillate about its mean position when the spherical balls start to spin and thus produce ripples). The three shafts are connected and hence form a system where the individual components can oscillate about their mean position when ever a disturbance is caused in its surrounding fabric. When the individual components oscillate, the alignment of the lasers would change. I need this system to be sensitive to minute translational displacements, so that when the ripples hit the system, the contraction and expansion of relative lengths between the lasers can be measured by some device connected to this system.

Below is an actual representation of LISA: enter image description here

My question is regarding the position instruments I am to use/make, what sort of instruments and/or devices would be able to detect the minute changes in the position of the interferometers and measure the curvature of the wave when the wave propagates in the elastic medium? Any help is appreciated.

  • $\begingroup$ Asking "how do I build my whole system" is way too broad. Is there any part of the design specifically that is giving you trouble? For example, do you not know how to get precise position measurements? If you have multiple problems, you can ask individual questions for each one. $\endgroup$ Jan 16 '17 at 13:04
  • $\begingroup$ @BarbalatsDilemma Sure, so it is alright if I post my parts of questions separately? $\endgroup$ Jan 16 '17 at 13:38
  • $\begingroup$ As long as each question is complete on its own. You can link to the other relevant questions if you want to provide more context $\endgroup$ Jan 16 '17 at 13:42

If I'm understanding your question correctly, you are asking how you can build a functional laser interferometer.

That is a pretty complex topic and impossible to cover in detail in a single answer. I'll however point you to Sam's laser FAQ, which is an excellent resource and has a few thoughts about building such from a CD-ROM drive: http://www.repairfaq.org/sam/laserlia.htm#liaint4

You may also want to consider using either time-of-flight or triangulation based laser distance sensors for your demonstration. They are nowhere near as accurate; they have a typical accuracy of 1 mm, as opposed to interferometry's 0.0001 mm. But their construction is significantly simpler and they are commonly available as premade modules.


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