Narrow Results

Well-crystallized SrBi₂Nb₂O₉ (SBN) thin films with smooth surfaces (the root mean square roughness is about 4.550 nm over an area of 2×2 μm²) are fabricated on MgO (100) substrates by the pulsed laser deposition technique at 750 °C under the oxygen pressure of 30 Pa. The nonlinear optical properties of the films are studied by using a single beam z-scan with ns pulses at 532 nm. SBN thin films exhibit an excellent nonlinear optical response, with the real and imaginary parts of the third-order nonlinear optical susceptibility being 4.139×10⁻⁷ esu and 1.104×10⁻⁷ esu, respectively. These show that SBN ferroelectrics thin films have potential applications in nonlinear optics.

Based on the Z-scan technology, the nonlinear absorption characteristics, the nonlinear refraction characteristics of ZnO nanoparticles dimethylformamide (DMF) solution and ZnO nanoparticles ethanol solution have been studied under the nanosecond (ns) laser pulses and the picosecond (ps) laser pulses. The experimental results show that the third-order nonlinear effect of ZnO nanoparticles ethanol solution is stronger than that of ZnO nanoparticles DMF solution under the ns laser pulses, and the third-order nonlinear susceptibility coefficient of the ZnO nanoparticles DMF and the ethanol solution are |χ⁽³⁾| = 2.15 × 10⁻¹²esu, |χ⁽³⁾| = 8.12 × 10⁻¹²esu respectively. The third-order nonlinear effect of the ZnO nanoparticles ethanol solution is similar to the ZnO nanoparticles DMF solution under the ps laser pulses. The third-order nonlinear susceptibility coefficient of the ZnO nanoparticles DMF and the ethanol solution are |χ⁽³⁾| = 1.16 × 10⁻¹⁴esu, |χ⁽³⁾| = 1.15 × 10⁻¹⁴esu respectively and the optical nonlinearities of ZnO nanoparticles under the ns laser pulses are better than that of the ZnO nanoparticles under the ps laser pulses.