  Heterodyne holography is an extremely versatile and powerful holographic
technique that is able to fully control the amplitude, phase and frequency of
both the illumination and holographic reference beams. Applied to vibration
analysis, this technique is able to detect the signal of the carrier or the one
of any vibration sideband. A complete analysis of the vibration signal can thus
be made, and 2D map of the vibration amplitude and phase in all points of the
surface of the vibrating object can be obtained. Since the sensitivity is
limited by shot noise, extremely low vibration amplitude (\textless{} 0.01 nm)
can be studied.
