Ref: Laser Metrology/ Encoders

Thanks very much for the help, I'll do some reading up on beam coherence.
Edmund optics is surprising, everything is about one figure cheaper than I was
expecting for lab quality equipment. Oh, and their small, micrometer
adjustable rotating tables look like a nice piece of work :)
I doubt I'll be trying this any time soon but I'll be keeping my eyes open for
a suitable laser unit.
Thanks again,
Stan