Laser Beams Deflected Off of Nothing but Air for First Time Ever in Breakthrough Patent Pending Process - The Debrief::An international team of scientists report that they have successfully used acoustics to deflect laser beams in an engineering first.
Doesn't need to be air "in space", there just needs to be air somewhere between the laser weapon and whatever it is you don't want the weapon to destroy...
... although it'd probably be easier to use a mirror. Maybe one pointing directly at the person holding a laser weapon. ;-)
A mirror? Light won't reflect off of nothing. The closest you'll get is gravitational lensing, but that requires about a galaxy's worth of mass to make any noticeable difference.