Was it you that linked to the waveguide approach to LIDAR some time in the past six months or so? The advantage of doing it that way is it's cheap as fuck and your slew rate is in the MHz range. The disadvantage of doing it that way is you're limited to super low power lasers which means you're going to be limited in range by pure physics.
Thing of it is, though, it opens LIDAR to new applications. Who knew 30 years ago that it'd be nigh onto impossible to buy a car without ultrasonic proximity sensors in the bumper nowadays? Being able to get high-resolution 3d topology on anything from 2m away with a $30-$40 (retail) component starts to make shit really fucking cool. I'm no booster of 3D printing but theoretically you could wave your sonic screwdriver over a key, upload it to your glowforge over bluetooth and dupe that fucker out of sheet aluminum with a button press. Or wave it over your mom's broken vase chips, flip them over, do it again, and have your 3d printer derive the piece that you can't find.
There are some cool applications for cheap-ass spacial imaging.