Two-reference-beam stroboscopic heterodyne hologram interferometry was used to study beams vibrating at frequencies up to 29.9 kHz. This method allows measurement of vibration amplitudes with an accuracy of 1/1000 of one fringe. As such it is particularly useful in studies of objects vibrating at amplitudes below one micron. Comparison between results obtained from holograms and those computed using the finite element method showed good correlation, in this study.
Ryszard J. Pryputniewicz,
"Vibration Studies Using Heterodyne Hologram Interferometry", Proc. SPIE 0955, Industrial Laser Interferometry II, (14 December 1988); doi: 10.1117/12.947681; https://doi.org/10.1117/12.947681