The 25MHz microphone

[hesener]

A new "optical" microphone can detect Sound waves up to 25MHz - now where is that tweeter that can reproduce that.....

Optical microphone "sees" broader sound spectrum | Electronics EETimes

 

[simon7000]

Nice cite. Not just high frequency response also low noise. Yes as mentioned lots of industrial applications. Of course the medical ones will take a while to get applied.

As to the directional or tracking microphone there is already one commercial competitor the TOA AM-1. Works well for public address systems. A bit pricey though.