I am looking for a way to increase the number of sensors in acoustic emission lab experiments. Fiber optics (DAS) is a natural candidate but the standard resolution is several meters. Is it possible to increase the resolution to cm and use the method on laboratory scale?
An array of microphones could probably do the job. An acoustic camera. But you get an awful lot of information to process. Near field Acoustic holography is a related possibility.
A grid of pairs of piezoelectric & thermal energy sensors placed at 2''-3'' can have a substantial increase in the resolutions, you can deduce the outcome in 3D representation of Thermally induced deformation in the energy. But yes as Anders Buen mentioned it would be a lot of data to process.
Please peruse the following links:
Article Distributed Acoustic Sensing - A new tool for seismic applications
Article Distributed Acoustic Sensing for Seismic Monitoring of The N...
Thank you for your answers. I always thought that 'acoustic emission' is quite a misnomer for my application. Microseismology could be a better name. I perform rock mechanics experiments, under high stress (tens to hundreds MPa), and I record P-waves emitted by cracking inside my sample using piezoelectric transducers (each channel is quite expensive, so I cannot increase the number considerably). In standard, field-scale seismology, as an addition to seismometers one can also use fiber-optic cables: the glass of the fiber-optic core is not perfect, there are some imperfections or density fluctuations, and it causes the light beam to scatter. In seismology the Rayleigh scattering is used. So, we send light through the fiber and record the scattering pattern. When a natural seismic wave passes through the fiber, the scattering pattern changes, and therefore we can analyze it. Obviously, the resolution is limited by the length of the cable used and the speed of light. In the lab tests, the overall length of the cable would be rather small -- 1 m at most, so we could record the scattering pattern changes at high rate.
The question I don't an answer to yet is whether there are enough scattering points at such small distance, and if not, can we manufacture them.
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