The newer systems can sample much faster (10-100 Hz), but they're still limited by the fact that they're measuring a hemodynamic signal that lags behind neural activity.
Which other strong and weak forces could [photonic,] sensors detect?
IIUC, they're shooting for realtime MRI resolution with NIRS; to be used during surgery to assist surgery in realtime.
edit: https://en.wikipedia.org/wiki/Neural_oscillation#Overview says brainwaves are 1-150 Hz? IIRC compassion is acheivable on a bass guitar.
I've purged a lot of the knowledge from that time from my brain, but from what I recall fNIRS takes a long time (on the order of multiple seconds) to take a single reading.
It also only really shows which regions of the brain are receiving more blood supply. While a huge improvement in spacial precision over EEG, it's still not anywhere near the same level of precision that a directly-wired nerve has.
That doesn't mean it's useless technology, just probably not viable for the low-latency, high-accuracy control you'd want for a military drone.
>Another question: is it possible to do ah molecular identification similar to idk quantum crystallography with photons of any wavelength, such as NIRS? Could that count things in samples?
I have absolutely no idea about molecular identification or quantum crystallography, so probably can't give you a good answer on that one.