I'm actually more interested in doing this at the larger macro scale than the micro scale. Imagine the ability to lift heavy objects with only sound. Weight rooms would look entirely different :)
Holo Display: generate the refractive voxel via ultrasonic convergent propagation fringe pattern, and light the voxel with IR that becomes higher frequency visible light color at point of interfearance/intersection.
PrHoteph: hyperplanes are your friends, may they guide your long distance acoustic whisper / ultrasonic voxel intersections.
Nothing new, this has existed in my household for the last 20 odd years -
"Hey honey, move this thing over there. No, an inch and a half to the left. NOPE - back to the right a few mm, and forward a little. Yup - wait...just a little bit more. There, you've got it!"