title: Excited-state absorption and sign tuning of nonlinear refraction in porphyrin derivatives.
abstract: The nonlinear absorptions and nonlinear refractions of free-base porphyrin (P2) and Zn-porphyrin (ZnP2) were studied using the Z-scan technique at 532 nm with different pulse durations. Both P2 and ZnP2 exhibit reverse saturated absorption attributed to excited-state absorption. The coordination of P2 by Zn ion can alter the nonlinear refraction sign from negative to positive at 4 ns pulse. The results indicate that the sign of self-lensing can be tuned by the coordination of Zn in the porphyrin derivatives. In the case of longer pulse duration, the thermal effect was enhanced to dominate the nonlinear refraction sign, leading to the negative nonlinear refraction repeated appearance.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100080, P. R. China.
authors.forename: Li
authors.initials: L
authors.lastname: Jiang
authors.forename: Tonggang
authors.initials: T
authors.lastname: Jiu
authors.forename: Yuliang
authors.initials: Y
authors.lastname: Li
authors.forename: Yunbo
authors.initials: Y
authors.lastname: Li
authors.forename: Junyi
authors.initials: J
authors.lastname: Yang
authors.forename: Junbo
authors.initials: J
authors.lastname: Li
authors.forename: Cuihong
authors.initials: C
authors.lastname: Li
authors.forename: Huibiao
authors.initials: H
authors.lastname: Liu
authors.forename: Yinglin
authors.initials: Y
authors.lastname: Song