title: Characterization of nonlinear properties of black phosphorus nanoplatelets with femtosecond pulsed Z-scan measurements.
abstract: The nonlinear properties of black phosphorus (BP) nanoplatelets (NPs) have been characterized with Z-scan measurements under 800-nm femtosecond pulsed laser excitation. A transition from saturable absorption (SA) to reverse saturable absorption (RSA) with the increase of laser intensity was observed in the open-aperture (OA) measurements. Simultaneously, closed-aperture (CA) measurements were carried out to investigate the nonlinear refractive index of BP NPs together, and a value of n(2) ≃(6.8±0.2)×10(-13) m2/W was obtained. The nonlinear absorption properties were analyzed according to the band structure of BP. A theoretical analysis based on SA and two-photon absorption (TPA) was used to determine the nonlinear absorption coefficients from the experimental results, and the TPA coefficient at 800 nm was estimated about (4.5±0.2)×10(-10) m/W.
authors.forename: Xin
authors.initials: X
authors.lastname: Zheng
authors.forename: Runze
authors.initials: R
authors.lastname: Chen
authors.forename: Gang
authors.initials: G
authors.lastname: Shi
authors.forename: Jianwei
authors.initials: J
authors.lastname: Zhang
authors.forename: Zhongjie
authors.initials: Z
authors.lastname: Xu
authors.forename: Xiang'ai
authors.initials: X
authors.lastname: Cheng
authors.forename: Tian
authors.initials: T
authors.lastname: Jiang