[alantrrs]

From the talks/podcasts I've heard, the goal is for the resolution to be good enough to measure and target individual neurons. Not sure where you get the ultrasound beacon part, but the images they have on their are using only red/near-infrared light. That being said, all of these is based on their own advertising. Curious to know, what are the fundamental physical constraints you are referring?

[pvarangot]

So if I don't misunderstand they heal the scattered wavefront by knowing that they are applying ultrasound to relax/contract a specific blood vessel. So while the image is created with information coming from reflected photons in the red/NIR spectrum they also know how to locate that physically by using a beacon.

This is all from old tech-talks and material that I saw. They were even very vocal about how they were able to do this because they were using this new piezoelectric microphone/speaker chips in the ultrasound frequencies.