The IR emitted is a structured laser light at IR frequencies. They're already using "lasers". The problem with using any sort of structured light is that your

The IR emitted is a structured laser light at IR frequencies. They're already using "lasers". The problem with using any sort of structured light is that your frequency can't be in the same band of any sort of flood lights (sunlight, ballasts, IR camera lights). It's also why X-Rays work well: it's a structured light (kind of) and can be used because we won't have a flood of XRays everywhere. The problem isn't with "IR": they should not be using a structured light solution. It's just not durable enough for 3d scanning applications. It's also why I've worked on a SLAM-like 3d scanner. Understanding geometry, corners, edges, and gradients are much more versatile in scanning, because it is passive. Our very eyes don't send out beams of light, and yet we manage a very accurate SLAM-like map inside our own heads. The problem with the Hololens is that until they switch to a vision-only system, they're going to be plagued with problems regarding IR sources (or whatever freq they choose). Source: me (3Dollar scanner, amateur radio operator, OpenCV reprap implementer)