Terahertz electro-optic properties of PbZr0.52Ti0.48O3 and BaTiO3 ferroelectric thin films

Electro-optic effects of PbZr 0.52 Ti 0.48 O 3 (PZT) and BaTiO 3 (BTO) ferroelectric thin films in the terahertz frequency range are studied with high-sensitive terahertz time-domain spectroscopy (THz-TDS). A linear response of PZT film with the linear electro-optic coefficient rc=6.73×10–11 m/V, and a quadratic response of BTO film with the second-order electro-optic coefficient Rc=1.42×10–17 m2/V2, are observed at the frequency of 1 terahertz under the applied static electric field less than 80 kV/cm. The calculation of rc and Rc based on the Landau-Devonshire free energy theory explains the different electro-optic effects of PZT and BTO well.