A single-beam interferometer with sub-ångström displacement resolution for electrostriction measurements

This paper describes a simple instrument for measuring very small electric field-induced strains. A single-beam interferometer with the capability of resolving 10^-4 Å or better in the displacement over a frequency range of 3-20 kHz is developed for measuring the direct electrostrictive coefficient of low-permittivity dielectrics. Problems associated with the measurement include mechanical and acoustical vibrations, the sample holder, significant disturbances from the vibration of electrical wires, and deleterious effects associated with high electric field. Procedures designed to eliminate or minimize these problems were developed by modifying the electrical wiring schemes and lowering the applied fields.