A Highly-Sensitive AC Interferometric Dilatometer

An interferometric-type dilatometer has been constructed which is capable of resolving AC linear displacements of 10-13 meter (0.001 Å) and can be used for the direct measurement of piezoelectric and electrostrictive deformations. Using DC servo stabilization of the optical pathlength, the mode of sensing the light intensity change generated by the alternating crystal deformation has been improved remarkably. Some experimental data are given on piezoelectric and electrostrictive crystals and ceramics.