There are some kind of light that the human eye can’t see, or it’s very difficult to do it. Like the Infrared (IR) or the Ultraviolet (UV). Of course is not the case here, because this is a laser light, and actually you can see it (but with some difficult, and very different from what the photos below show).

These photos were taken to an Logitech RX 1000 laser mouse.

I must confess that it was a bit difficult to focus on the purple laser. As the light is concentrated in one point, the minimal movement of the camera make the laser disappear from focus. But after a few minutes, I could take these photos…