Absolute measurement of in-plane vibrational distribution in piezoelectric resonators based on laser speckle interferometry

A full-field imaging method has been developed for rapidly measuring absolute in-plane vibrational distribution of piezoelectric devices. This method is based on the synchronized laser speckle method. To confirm the measurement accuracy, a quartz plate with a small mirror attached to a lateral surface is used. The plate is excited by an external ceramic vibrator, and the absolute vibrational displacement is measured with a Michelson interferometer with optical components, including the small mirror. The amplitude of the in-plane displacement is obtained from data and statistical processing of the captured speckle images and is compared with the displacement obtained with the Michelson interferometer. Experiments showed good agreement between the two displacements, validating the proposed method.