Re: Igram Artifact


Light grease (Vaseline) on the back face will remove this, I agree this looks very likely to be a cause!!

Kind regards,


From: <> on behalf of Gleb1964 <gleb1964@...>
Sent: 29 April 2020 09:48
To: <>
Subject: Re: [Interferometry] Igram Artifact

looking on your image I think that it is not shutter speed or integration time related. I see intersection of two sets of fringes, influencing each other. Sort of like a double light source.
Not clear what can be reason for that. How does laser beam looks on a long distance propagation? Does it getting double?
Do you have reflection of reference beam from mirror back? It can be significantly reduced by applying a drop of black paint or even tape set on the mirror back in a place of reference beam strike it.


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