Optical nonlinearities of five new organophosphorus fullerene derivatives with similar structures were determined by the Z-scan method by use of a nanosecond-pulse laser at 532 nm. The experimental results demonstrate that the five derivatives have much larger excited-state absorption and nonlinear refraction than C<sub>60</sub>. The excited-state absorption cross sections are nearly two to three times that of C<sub>60</sub>. Using a five-level model to fit the experimental data, we obtained some parameters such as excited-state absorption and refraction cross sections. A simple analysis of correlations between molecular structure and nonlinear properties is given. Optical nonlinearities of the five new organophosphorus fullerene derivatives were compared with those of some other kinds of fullerene derivatives, and the results show that the nonlinearities of the new derivatives are the larger.
© 2003 Optical Society of America
(160.4330) Materials : Nonlinear optical materials
(190.0190) Nonlinear optics : Nonlinear optics
(190.4710) Nonlinear optics : Optical nonlinearities in organic materials
(190.5330) Nonlinear optics : Photorefractive optics
Zhi-Bo Liu, Jian-Guo Tian, Wei-Ping Zang, Wen-Yuan Zhou, Chun-Ping Zhang, Jian-Yu Zheng, Ying-Chun Zhou, and Hua Xu, "Large Optical Nonlinearities of New Organophosphorus Fullerene Derivatives," Appl. Opt. 42, 7072-7076 (2003)