I keep pondering those laser systems that a man overboard (MOB)or other
person in need of rescue is s'posed to use to signal to a boat. It has
the makings of a good system but it has near fatal flaws. I hear it is
really difficult to get the beam onto the target so it is seen.
We need something kinda like that nearly as effcient power wise whose
beam is broader and possibly flashing. This cannot be too hard. Most
semiconductor lasers can be pulsed and plastic optics to take a
parallel beam and put it into a specific solid angle are well known
(google on Compound Parabolic Concentrators if you like awful math).
Put a sight on it so that when your target is in the sight ring you
know it is illuminated and have a trigger to activate it for however
long you like...........

try a set of 4 or 5 beams...take a look at the system the FAA is using
on alerting pilots of intrusion into closed air space around wa
dc...they have mounted some laser warning systems ontop of some key
buildings w/in the city of wa dc....