Femtosecond Lasers midair Plasma

It is a little unclear how the stereo space will be formed, will it be the same stereo format, that is, two laser sound sources that in turn will form apparent, imaginary sound sources? Then there can be no talk of any 3D.
 
Like other types of plasma speakers, this technology would generate lots of nasty gasses. Perhaps not ozone but nitrogen oxides aren't very benign, either. Doing it in pure nitrogen or argon would take care of that but then you need to periodically refill the tank. Just recently I bought a 40CF argon tank + regulator (for a welder) and the combination cost me about $140 -- not including the cost of filling it. That may run about $50 per fill.

Another problem is the cost of the laser. Not cheap, at least not at the moment. WAY more than an argon tank....