Optically tuned dielectric property of ferroelectric PZT/STO/PT superlattice by THz spectroscopy

- Optical-tuned dielectric property of PZT/STO/PT superlattice were investigated.
- The trilayer superlattice realized a high modulation depth in THz range.
- A comprehensive model was used to analyze the dielectric property.
- Results displayed the STO layer enhanced the dielectric property.

The dielectric spectra of ferroelectric Pb(Zr0.52Ti0.48)O3/SrTiO3/PbTiO3 (PZT/STO/PT) superlattice under an external optical field were investigated at room temperature by time-domain terahertz (THz) spectroscopy. Results showed that the real and imaginary part of permittivity were increased roughly upon application of an external optical field, and tuned by 78.16% and 85.65% respectively. It could be interpreted as softening of the soft mode and increasing of the damping coefficient and oscillator strength. Furthermore, the central mode was observed in the tricolor thin film, and the frequency of the central mode was also increased along with the optical power.