title: Unidirectional optical Bloch oscillations in asymmetric waveguide arrays.
abstract: We present an analytical proof of the existence of unidirectional optical Bloch oscillations in a waveguide array system. It is shown that the presence of nonreciprocity in the system allows for a complete normal-mode dephasing in one of the propagation directions, resulting in a unidirectional breakdown in Bloch oscillations. A model system consisting of an array of transversely magnetized asymmetric Si/SiO2 waveguides with a magneto-optic cover layer is presented. Large index contrasts between film and cover are critical for practical realizations.
authors.affiliation: Department of Physics, Michigan Technological University, Houghton, Michigan 49931, USA.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Kumar
authors.forename: Miguel
authors.initials: M
authors.lastname: Levy