Re: Igram Artifact
Light grease (Vaseline) on the back face will remove this, I agree this looks very likely to be a cause!!
From: Interferometry@groups.io <Interferometry@groups.io> on behalf of Gleb1964 <gleb1964@...>
Sent: 29 April 2020 09:48
To: Interferometry@groups.io <Interferometry@groups.io>
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.