Nano-displacement measurements of a new piezoelectric flextensional actuator by using a high dynamic range interferometry homodyne method

Piezoelectric flextensional actuator (PFA) devices consist in a technology in development, with increasing number of applications in precision mechanics such as nanotechnology equipments, electronic microscopy instruments, cell manipulation systems, microsurgery tools, and lens positioner for laser interferometer to name a few. In turn, optical interferometry is an adequate technique to measure nano/ micro displacements and to characterize these PFAs. An efficient method for optical phase detection is the n-commuted Pernick method (n-CPM), where only a limited number of frequencies in the magnitude spectrum of the photo detected signal are used, without the need to know the phase spectrum. The n-CPM has the advantages of being passive homodyne, direct, self-consistent, and is immune to fading. The dynamic range for optical phase measurements is from 0.2 rad to 100π rad. In this work, by using the n-CPM, a new PFA prototype designed by topology-optimization method is tested in terms of displacement linearity (relative to applied voltage) and frequency response.