Effect of optical pump on Pb_(0.52)Zr_(0.48)TiO_3 ultrathin film on La/ViO_3 /Si substrate in the terahertz region

摘要

PZT (Pb0.52Zr0.48 TiO3) ultrathin film (12 nm) was deposited on LNO (LaNiO3) film/silicon substrate by magnetron sputtering. XRD and AFM results show the highly oriented ultrathin PZT film with smooth surface suitable for optical modulation. The figure of merit K was observed increased to highest 0.25 with the 532 nm continuous-wave (CW) pump power increasing to 500mw at 0.5 THz. The variation of the tunability of dielectric permittivity and the loss were attributed to the built-in electric field caused by the optical pump. It was also found that the conduction loss was predominated in the entire loss when the external field increased.