Laser designators use an eye safe laser with a beam that is invisible and fires a series of coded pulses of light.
Northrop Grumman's LLDR, using an eye-safe laser wavelength, recognizes targets, finds the range to a target, and fixes target locations for laser-guided, GPS-guided, and conventional munitions. When a target is marked by a designator, the beam is invisible and does not shine continuously. Instead, a series of coded pulses of laser light are fired. 
