【摘要】 利用时域有限差分法数值求解速率-场强方程,研究了一系列共价连接的氧化石墨烯-卟啉复合材料在纳秒时域内的光限幅性质和双光子吸收.计算结果表明,氧化石墨烯-卟啉复合分子与单独的卟啉分子相比展现出增强的光限幅效应,并且有着更大的双光子吸收截面.与之前得到的含重金属的卟啉分子具有更强非线性光学性质的结论不同,不含金属元素的卟啉分子与氧化石墨烯结合后展现出了更强的非线性光学性质.理论计算的结果与实验测量符合较好.此外,着重研究了介质的厚度和脉冲宽度对分子双光子吸收截面的影响.结果表明,随着介质厚度的增加或者脉宽的变宽分子的动态双光子吸收截面增大.更多还原

【Abstract】 Optical limiting(OL) properties and two-photon absorption(TPA) of a series of covalently linked graphene oxide-porphyrin composite materials have been investigated by numerically solving the rate equations and field intensity equation with an iterative predictor-corrector finite-difference time-domain technique in nanosecond time domain.Our results show that graphene oxide-porphyrin composites exhibit enhanced OL behavior and possess larger TPA cross section compared with individual porphyrins.Interestingly,unlike the previous result that porphyrin with heavier central metal shows better nonlinear abilities than that without metal substitute,graphene oxide-metal free porphyrin composite has stronger nonlinear absorption properties compared with graphene oxide-metal porphyrin composite.The computational results are in reasonable agreement with the experimental ones.Special attention has been paid to the influence of thickness of the medium and pulse width on TPA cross sections,which presents that larger TPA cross sections are obtained as the medium is thicker or the pulse duration is wider.更多还原