Thanks for the kind words! I know Jem from the holography forum, I think he's the one that turned me on to this site.
When I mean orders in a grating, it's how many beams are coming out of it. The straight through beam is the zero order, and there are plus and minus 1, 2, 3 ... to the right and left of the central one. I guess for these uses the more the merrier! And having diffraction both horizontally and vertically to give a square pattern would also be desirable.
About how big would be useful? I'm assuming that the grating would be downstream of the galvo's, so would something about 2" by 2" square be about right?
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