title: Slow light and superluminality in Kerr media without a pump.
abstract: Subluminal and superluminal propagation of a light pulse in Kerr materials has been investigated. Group velocities as slow as much less than 1 mm per second to as fast as negative several thousands meters per second can easily be obtained in the Kerr medium, which possesses a large nonlinear refractive index and long relaxation time, such as Cr3+-doped alexandrite, ruby, and GdAlO3. The physical mechanism is the strong highly dispersive coupling between different frequency components of the pulse.
authors.affiliation: Department of Physics, Hampton University, Hampton, Virginia 23668, USA. qiguang.yang@hamptonu.edu
authors.forename: Qiguang
authors.initials: Q
authors.lastname: Yang
authors.forename: Jae Tae
authors.initials: JT
authors.lastname: Seo
authors.forename: Bagher
authors.initials: B
authors.lastname: Tabibi
authors.forename: Huitian
authors.initials: H
authors.lastname: Wang