[jcgrillo]

Too late to edit, and somewhat off topic, but I wonder if you could package an interferometer in such a way to work for calipers?

https://caltechexperimentalgravity.github.io/IFO.html

[jcgrillo]

Again, too late to edit, but there's some interesting related content here:

https://hackaday.io/project/5283-potpourri/log/21475-laser-i...

https://hackaday.com/2015/07/24/self-built-interferometer-me...