optical stages and alignment, sending beams of light to specific locations.

https://en.wikipedia.org/wiki/Optical_table

Optical suppliers are

https://www.edmundoptics.com/ (highly recommend ordering their catalog)

https://www.newport.com/g/optical-tables

https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=70...

Youtube channels on optics

https://www.huygensoptics.com/

https://www.youtube.com/@BreakingTaps

Man, Edmund Scientific is a throwback. They used to have an awesome surplus store in NJ full of all kinds of nerd stuff.