Frequency-selective imaging of acoustic vibration components by photorefractive interferometry

A photorefractive interferometry method is presented that demonstrates the feasibility of selectively visualizing an acoustic vibration component at a specific frequency of interest in the presence of strong vibrations at other frequencies. This result serves as a proof of concept for using the approach for detecting weak vibration components induced by defect-induced acoustic nonlinearity in the presence of the very strong other vibrations that generate the nonlinearity. The obtained vibrometric image sequences are free of spurious influences of strong vibration components induced by the nonlinear optical effects that are typically severely distorting the imaging of complex vibrations using classical interferometric imaging techniques.