I would like 100,000 pluses per revolution, 200,000 would be better. That makes the standard optical disk unrealistically large; under 2” would be OK for a diameter.
I looked at using gears and at first they look like a good option but even the ones that say they are zero backlash, have only 1.5 arc min. accuracy.
There are very small high resolution encoders, but I can not afford them. With all the inventive people on this forum we should be able figure something out.
Gary