title: Ultrafast saturable absorption in topological insulator Bi₂SeTe₂ nanosheets.
abstract: Topological insulator (TI) Bi2SeTe2 nanosheets with very regular hexagonal morphology were synthesized by a hydrothermal route. Open aperture (OA) z-scan method was performed to measure the saturable absorption (SA) characteristics of the as-prepared TI Bi2SeTe2 nanosheets. The measured modulation depth, saturation intensity and nonsaturable loss of the sample were 61.9%, 4.46 GW/cm2 and 4.5% respectively. An ultrafast intraband scattering time of ~50 fs was obtained through simulating the SA curve, which indicates the TI Bi2SeTe2 nanosheets may be a good candidate for mode-locking material.
authors.forename: Hang
authors.initials: H
authors.lastname: Zhang
authors.forename: Xin
authors.initials: X
authors.lastname: He
authors.forename: Wei
authors.initials: W
authors.lastname: Lin
authors.forename: Rongfei
authors.initials: R
authors.lastname: Wei
authors.forename: Fangteng
authors.initials: F
authors.lastname: Zhang
authors.forename: Xi
authors.initials: X
authors.lastname: Du
authors.forename: Guoping
authors.initials: G
authors.lastname: Dong
authors.forename: Jianrong
authors.initials: J
authors.lastname: Qiu