Illumunation and Designation are two seperate tasks.
Designation is using a laser to aim a weapon or point accurately at something in a way that can only be seen with night vision. 5mw of 904nm works well, it is far enough from gen 3's peak sensitivity that it doesn't bloom and overwhelm the optic. commercially available civilian legal fda approved lasers are in the 820to 850nm range and are sub 0.7 mw, these work well too. being in the peak sensitivity range they require much less power. higher powered military lasers exist 5-250mw but these have other purposes than aiming a rifle and are too powerful.
illumination is providing more ir light when there isn't enough ambient ir light to provide a quality image. examples would be a basement, deep in the woods, or an extremely cloudy night. this is usually done with ir leds or visable lights behind a filter. some are low powered to provide just enough light to see up close, map reading and finding your footing. others are higher powered for providing illumination at longer ranges, and some can be focused for flood or spot. 200mw ir leds are considered high power for night vision, providing more illumination than a searchlight. one manufacturer claims 800 yards from 100mw. that light reflecting off something at close range could cause damage to your optics.
night vision is extremely expensive, and extremely sensitive. they don't require high powered light at all. a 15w red tailight looks like hid highbeams shining across my yard. its easy to cause terminal damage to a optic.
