The beamsplitter in Michelson interferometer influenced the light, going through respectively being reflected by 90°.

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Image source: Wikipedia

Has somebody of you ever see what shape has the spot from a laser source on the observation screen if one of the mirrors is not installed?

Edit: There is a comment:

I have not and I no longer have access to a Michelson interferometer. If you have observed fringes then they might be due to the multiple reflections from the top and bottom of the beam splitter and the compensator.

  • $\begingroup$ Not sure what your question is, but if your asking which mirror will produce a spot on the screen if the other mirror is not present. The answer is both mirrors, A or B, will produce a spot on the screen if the other mirror is gone. $\endgroup$
    – Lambda
    Mar 10, 2017 at 7:10
  • $\begingroup$ Lambda, I'm asking has one removed one of the two mirrors and what he -the observer - see on the screen. $\endgroup$ Mar 10, 2017 at 8:27

1 Answer 1


Yes I have blocked the light from one of the mirrors. The image on the screen is simply the light from your laser projected onto the screen. The interference pattern goes away. The setup below produces the two images that you see. I have two beam splitters, one is just plate glass, because I wanted to show the image that returns to the laser too. If I block either mirror the interference patterns go away. I hope this helps. enter image description here enter image description here

  • $\begingroup$ Thank you. Unfortunately I hoped to see from the metal lattice of the beam splitter fringes on the screen. Could you please increase the distance of the observer screen to the beam splitter to say 2 ... 3 meters? $\endgroup$ Mar 10, 2017 at 15:13
  • $\begingroup$ Not sure what you're asking. $\endgroup$
    – Lambda
    Mar 10, 2017 at 15:38
  • $\begingroup$ Please make the distance from the beam splitter to the observed image bigger. In the best case to a distance of 2 or 3 meters. Thanks in advance $\endgroup$ Mar 10, 2017 at 15:47
  • $\begingroup$ Could you show an image of the screen before and after blocking one mirror? Thanks $\endgroup$ Mar 10, 2017 at 17:23
  • $\begingroup$ I don't have a pic of that, but they stay the same size and shape. They lose the interference pattern and lose some of their brightness. They essentially become pale reddish disks of light. $\endgroup$
    – Lambda
    Mar 10, 2017 at 17:37

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