Nonlinear optical properties of lanthanum-modified lead zirconate titanate investigated by the femtosecond Z-scan technique

摘要

We used a closed-aperture Z-scan technique to study the nonlinear optical refractive index of lanthanum-modified lead zirconate titanate (PLZT) (9/65/35) ceramics. Our laser light source was a mode-locked titanium-sapphire laser, the output pulse width was approximately 100 femtoseconds at a wavelength of 790 nm, and the repetition rate was 10 kHz. We found that PLZT had a large, positive nonlinear optical refractive index, n_2 ＝ +(3.1 ± 0.6) × 10~(-8) esu, and its third-order susceptibility was calculated to be x~(3) = (9 ± 1.8) x 10~(-9) esu. When an electric field (E) was applied to the PLZT, n_2 increased along in direct proportion to E~2. We speculate that the increase in n_2 was caused by the more ordered structural arrangement of the PLZT imposed by the applied electric field. The results show that PLZT has potential applications in fast, electric-field-controlled nonlinear optical elements.