Do there exist materials that:
- React to electrical pulses having frequency in the band 2-10Hz with a very low frequency response (near to DC), - Have a measurable reaction, where measurable means that I can directly transduce the signal into an electrical one by connecting in some way the material to an electronic circuit,
- The reaction is easy to measure, easy means that the measurement circuit is very elementary,
- Dissipates very low power (microWatts (or orders about 10^2 microWatt ) if possible).
I actually don't care about the way these materials react, they can also emit some light whose spectrum varies with the pulses frequency.