Hey there, I'm doing a Michelson Interferometer for my final Physics project, and my partner and I are having some difficulties. We have our beam splitter set up 45 degrees from the light source (a simple red laser) and 2 mirrors set up in such a way that the one directly across from the beam splitter from the laser is 90 degrees to the laser, and the other parallel to the laser (so that the beam is also reflected off the surface at 90 degrees from the beam splitter). Our problem is when our beams come back together on the beam splitter, the light projected on the piece of paper we have is much weaker, and the laser is the same size with no visible fringes. This is very frustrating as we have spent a great deal of time trying to fix this over and over again. We have even puffed minute amounts of baby powder over our interferometer to see the laser beams reflecting off the mirrors to confirm that our angles were properly set. We have spent many hours trying to figure out why we can't see anything and I'd really appreciate some advice from this community! The following picture is basically the same set up as our interferometer. I will try to get a picture from my partner since the device is at his house currently so that you may have a better understanding as to what might be wrong with it. http://www.clu-in.org/programs/21m2/openpath/op-ftir/images/exhibit1.gif Thank you for your time and consideration.