Theoretical Optic Problems. Please help :)

For a scientific project I want to scan a large cone shaped beam.
To reach a single point with high power density that can be moved fast.

My problem is that the galvo mirrors in my price range have to be very small because of the scanning speed they work at and I can't expand the beam behind the galvo because it wouldn't be always centered in the beam expander lens array.

My second solution would be to actually cross two scanned beams in mid air but I haven't enough experience to evaluate whether galvos are accurate enough for that.

Thanks in advance for every reply

Bump for a serious question

I don't see how crossing 2 beams will produce anything like a cone. You could easily use the small galvo to produce an inverse cone effect by either moving the beam in a circle, or by having the beam focused on the galvo mirror after which it will expand out in a cone, but in either case, the point of the cone will be on your mirror rather than your projection surface. You could have a focusing lens after the galvo, but like you said, the alignment will move around producing a coma effect on your point.

Put a long focal length lens directly before the galvos. Simple as.