Laser-Based Night Vision Works at Long Ranges

Night vision isn’t magic and passive night vision can’t see in pitch darkness — it can only amplify whatever little bit of light is already there. But active night vision has some interesting quirks that you can harness to do things that almost seem magical. For example, YouTuber Project 326 built their own night vision system that works at long ranges.

To understand how this works, you first need an overview of the basic principles of active night vision. It is actually really simple: it shines a bright light. But there is a trick, which is that the bright light is in the infrared spectrum, so we humans can’t see it with our naked eyes. Cameras, however, can see infrared light. So active night vision goggles have cameras that pick up the scene illuminated by infrared and show you the result on a display.

Typically, you want to see a lot of area and so most night vision setups use the infrared equivalent of a floodlight — though narrower beams are advantageous in covert situations. But if you tighten up that beam so it is essentially a laser, you can illuminate a distant object or small area. If your night vision camera is telescopic, you can see that distant illuminated area pretty well.

This is a good time to point out that lasers are dangerous. Project 326 put effort into finding a kind of safe laser and ran it at low power, but this could still blind someone pretty easily. So, don’t do this.

Disclaimer out of the way, I will say that Project 326 used a VCSEL (vertical-cavity surface-emitting laser), which is basically an array of LEDs crammed together. That’s rated for 4W, but they didn’t need to go that high. An optical system focuses the laser beam to the target range.

The camera system was pretty easy, because all digital cameras detect infrared light — manufacturers just put special lens filters on to block that light. Remove the infrared filter and the camera will capture infrared light, in addition to the visible spectrum. Project 326 simply attached the filter-free camera to a telescope, with a 3D-printed mount system that offers adjustability for aligning the telescope and laser.

It isn’t perfect (alignment took an hour), but testing at a hotel overlooking a beach proved that it does work at up to about 1km, which is very impressive.