title: Tunable nonlinear double-core PT-symmetric waveguides.
abstract: We propose a scheme for creating a tunable, highly nonlinear defect in a one-dimensional photonic crystal with an embedded atomic cell filled by a mixture of two isotopes of three-level atoms. The defect creates an effective double-core waveguide. The induced refractive index for a probe field can be made parity-time (PT) symmetric by means of a proper combination of a control field and a Stark field; hence the complex defect potential obtained contains double-well real and linear imaginary parts. We also show that it is possible to form various stable nonlinear defect modes supported by the focusing nonlinearity of the system.
authors.forename: Chao
authors.initials: C
authors.lastname: Hang
authors.forename: Dmitry A
authors.initials: DA
authors.lastname: Zezyulin
authors.forename: Guoxiang
authors.initials: G
authors.lastname: Huang
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Konotop
authors.forename: Boris A
authors.initials: BA
authors.lastname: Malomed