Warn Laser

If you don't want to see anything you need something out side the range 380 to 780 nm (that's the range the human eye typically sees it can vary quite a bit.). longer Wellenlänges go towards infrared and shorter is towards ultraviolet. A sufficiently short or long Wellenlänge is completely invisible to the human eye and most camera's without filters. The infrared laser at a beam frequency of 1064nm is manufactured in the form of CW (continuous wave) laser diodes.

Take special care with lasers as powerful as that one. These lasers will burn your eyes much faster then you can blink. The danger of IR radiation is that you can't see it, so you won't look away until possibly far too late. The 1064nm Wellenlänge is just barely visible, increasing the temptation to look closer and longer.