I am trying to understand how laser show galvanometer systems like this one create high-resolution movement, and generate drawings of reasonable precision (w.r.t. minimum beam angular-deflection step size) on a surface several feet away.
The Wikipedia page has very limited information about the modern version, although a paragraph claims high-speed mirror galvanometers are used for laser ablation, marking, etc., which are of course high-precision applications.
Given laser show devices are so popular, but the documentation a bit lacking, I would appreciate an explanation, especially of the closed-loop part which these laser show "scanners" claim to contain.
Do they use a stepper motor (and just claim it's essentially closed loop), or do they have a standard DC motor with a magnetic/optical encoder of some sort?
Also, what kind of angular resolution is a system like the above linked product, typically capable of?
As may be clear from these questions, I am trying to see if it would be apt to repurpose one of these for my own project, where I need to attain laser-marking at approx. 50-75 microns resolution at a few centimeters away (unfortunately, physical constraints prevent use of a gantry system that might be seen in 2D plotters/3D printers).