Fiber-optic based method for the measurements of electric-field induced displacements in ferroelectric materials

A novel technique for the measurements of electric field-induced displacements in ferroelectric materials is presented. The method relies on a high sensitivity of the fiber-optic probe (Fotonic Sensor™, MTI Inc.) that measures the displacement of a specially designed cantilever beam having both electrical and mechanical contact with deforming sample. In this way, the major disadvantages of the standard Fotonic Sensor technique can be avoided. The method provides relatively high sensitivity (down to ∼4 Å), high stability (7% over 8 h), and sufficiently broad frequency range. The capabilities of the proposed measurement setup are validated by the strain measurements in bulk Pb(Zr,Ti)O₃(PZT) ceramics and thin films.