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 103 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.