Measuring amplitude and phase of microvibrations by heterodyne speckle interferometry.

Amplitude and phase of both in-plane and out-of-plane vibration components are measured in real time using heterodyne speckle interferometry. Microvibrations with amplitudes down to 1 nm and frequencies up to 5 MHz were analyzed at a spatial resolution of 35 microm. Amplitude and phase measurements were performed with an accuracy of better than 6% and 4 degrees , respectively. This permits complete determination of the mechanical movement of a vibrating surface.