You could try sheilding the cameras from RF from the laser by enclosing
them in (or at least putting them in the shadow of) a screen shield; you
can use either aluminized mylar coated house insulation (a clever
approach I learned from George Augustine, or aluminum flyscreen
(copper or bronze is actually better but only marginally so) or putting
up aluminum sheets, or even maybe foil, and grounding it to the either a
pipe or the ground in the electrical system.  How you place it depends on
the position of the laser and your cameras.  The added advantage of this
is that it should help with other hihg-voltage RF leaking from arc lamps
and other similar devices.
 
Tony Moss
Auburn