Homodyne and heterodyne optical interferometry for frequency dependent piezoelectric displacement measurement

The electromechanical coupling in piezoelectric materials has been widely studied however a unified view of this interaction as function of frequencies using different measurement techniques has not previously been available. This study examines and compares multiple optical based homodyne and heterodyne interferometry techniques for displacement measurement over a wide range of frequencies and including a comparison made by using a commercial Laser Doppler Vibrometer. Ferroelectric lead titanate PbTiO3 with high ferroelectric strain is studied in this work. Frequency dependence of the electromechanical displacement is obtained using multiple techniques and the emphasis is given to near resonant frequency interrogations.