Application examples
Optical generation and detection of elastic waves

Here we present some results illustrating the capabilities of the compact heterodyne probe developed in our laboratory and marketed by B.M. Industries. The sensitivity of this instrument is highlighted in figure 23 . It shows the amplitude of the thickness vibration, at a frequency of 160 kHz, of a mirror-bearing piezoelectric ceramic (PZT) transducer. The jump of 3 × 10 ^–5 nm shows that an amplitude of 10 ^–5 nm is detectable. The theoretical limit corresponding to the experimental conditions (2 mW He-Ne laser, B = 1 Hz) is almost reached [formula