The J 1 …J 3 method for linear readout of dynamic phase change in a flextensional piezoelectric actuator

A new improved version of the J1…J4 interferometric method for optical phase measurements, named J1…J3 method, is described, which is of easier implementation and is more stable to phase drift than the original one. This new spectrum technique is used to characterize a flextensional piezoelectric actuator by measuring its nanometric displacement amplitudes.