几种新型金属配合物热致三阶非线性光学特性

利用连续激光Z-扫描方法研究了过渡金属Ni、Cu、Pd的新型有机配合物的热致三阶非线性光学特性。结果表明：在488nm和632．8nm波长连续激光激发下，这几种配合物的光学非线性折射主要来源于热效应。并由实验曲线计算了它们的热光系数dn／dT及热致非线性折射率n2。通过比较，发现热致非线性折射率与配合物分子结构、激发波长及在该波长下的线性吸收强弱有关。金属中心原子的原子序数越大，热光系数和折射率也相应的越大。在488nm波长激光激发下的dn／dT和n2大于该配合物在632．8nm波长激发下的dn／dT和n2，在同一波长下，化合物溶液在该波长下的吸收越强，其dn／dT和n2值也越大。

Thermally-induced Third-order Optical Nonlinearity of Several Novel Metalorganic Compounds

When a medium was excited by a laser, the thermal effect always existed. Especially for a laser whose pulse width was beyond ns.or the sample had large absorption,the effect could not be neglected.So the investigation of the thermally induced optical properties of a compound was very important. The thermally-induced nonlinear refraction index changes of a sample always covered the change of quick electron effect when the refraction index was measured by some techniques. The thermally-induced third-order optical nonlinerity property of the coordinated compound of three kinds of transition metals Ni, Cu and Pd was studied by Z-scan technique for the first time. Both 488 nm and 632.8 nm CW laser were used for excitation. The result showed that the optical nonlinear refractions of the three compounds under CW laser resulted from the thermal effect, and they had no nonlinear absorption. By combining experimental curves and the thermal effect theory,we calculated the thermoptical coefficient dn/dT and the thermal-induced refractive index n_2 of the compounds.By comparison,it could be discovered that the thermoptical coefficient dn/dT and the thermal-induced refractive index n_2 of the three compounds were different from each other under different excitation conditions. In general, the values of dn/dT and n_2 under 488 nm laser excitation were bigger than those under the excitation of 632.8 nm laser,this was in according with other paper's results. Moreover, the values of dn/dT and n_2 of the compounds also depended on the linear absorption under certain condition.The stronger the absorption,the bigger the values.Finally, the atomic number of the central metal atom of the coordinated compounds influenced on the values too.If the central metal atomic number was bigger,then the thermoptical coefficient and the thermally-induced nonlinear refractive index of the compound were bigger.