Wondered about that on the drive into work this morning. It's a long drive.

My first thought was that the plasma might be created at the intersection of one or more beams...but I've found a few short articles about it and they keep talking about a "a focal point of focused laser light." (sic) There's no mention of multiple beams.

One thing I don't understand: how do they get a laser beam to stop and cause something to glow at a certain distance from its source?

I don't think they're stopping it, though that'd be an awesome trick. They're creating a focal point, which creates a plasma "node." Unless the glowing plasma becomes opaque (I don't have much experience with plasma, myself), I'd imagine the beam continues on it's path past the focal point...in which case the display probably creates an interesting light show on the ceiling.