Laser interferometer for the study of piezoelectric and electrostrictive strains

Abstract

A modified Michelson interferometer is used to study the strain properties of piezoelectric and electrostrictive materials. For small displacement, a feedback loop is introduced to stabilize the system against the low-frequency optical path-length drifting and the system is capable of resolving displacements of the order of 10−3 Å. For the strain induced by domain switching, a dual-channel signal detection scheme is used which automatically reads out the displacement of the sample. The effect on the measurement of the sample bonding to a substrate and other related problems are discussed.