Square or rectangle works for me.. a beam's a beam (as long as its a laser ) for beamshows anyway. What kind of laser is this y'all were using?
A foot at 20 meters? That divergence doesnt sound real good. Probably could tighten that up a bit with cylindrical or grin lens? Sounds cool though..
Talking about BIG red beams, here is one that I thought I would share with you all. It is called appropriately enough, BigRED.
It is by a friend, Casey Stack, who among many other things is one of the co-authors of the ilda test pattern.
2.5watts spec (3Watts)
629nm direct diode (not a single)
CW or pulsed, directly modulated.
deliverable in various configurations.. but this one represents 15mm
beam diam and about 4mrad divergence...
Multimode
I dont mind a fat beam as long as it's super bright and the divergence is ok. Maybe it could be re-collimated with a rifle scope ( I've heard of this being done- dont know if it works..)
Come on dave... It IS over two watts... I'm not too find of the higher reds but it has a nice footprint. It'd be nice to see if he can get that much power but in 670 or so.