title: Generation of Nonlinear Vortex Precursors.
abstract: We numerically study the propagation of a few-cycle pulse carrying orbital angular momentum (OAM) through a dense atomic system. Nonlinear precursors consisting of high-order vortex harmonics are generated in the transmitted field due to carrier effects associated with ultrafast Bloch oscillation. The nonlinear precursors survive to propagation effects and are well separated with the main pulse, which provides a straightforward way to measure precursors. By virtue of carrying high-order OAM, the obtained vortex precursors as information carriers have potential applications in optical information and communication fields where controllable loss, large information-carrying capacity, and high speed communication are required.
authors.affiliation: State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China.|Department of Physics, Shanghai Normal University, Shanghai 200234, China.|University of Chinese Academy of Sciences, Beijing 100039, China.
authors.forename: Yue-Yue
authors.initials: YY
authors.lastname: Chen
authors.affiliation: Department of Physics, Shanghai Normal University, Shanghai 200234, China.
authors.forename: Xun-Li
authors.initials: XL
authors.lastname: Feng
authors.affiliation: State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China.
authors.forename: Chengpu
authors.initials: C
authors.lastname: Liu