title: Tunable positive and negative refraction in optically induced photonic lattices.
abstract: We study tunable refraction of light in one-dimensional periodic lattices induced optically in a photorefractive crystal. We observe experimentally both positive and negative refraction of beams that selectively excite the first or second spectral bands of the periodic lattice, and we demonstrate tunability of the output beam position by dynamically adjusting the lattice depth. At higher laser intensities, beam broadening due to diffraction can be suppressed through nonlinear self-focusing while preserving the general steering properties.
authors.affiliation: Nonlinear Physics Centre and Centre for Ultrahigh-bandwidth Devices for Optical Systems, Research School of Physical Sciences and Engineering, Australian National University, Canberra ACT 0200, Australia. crr124@rsphysse.anu.edu.au
authors.forename: Christian R
authors.initials: CR
authors.lastname: Rosberg
authors.forename: Dragomir N
authors.initials: DN
authors.lastname: Neshev
authors.forename: Andrey A
authors.initials: AA
authors.lastname: Sukhorukov
authors.forename: Yuri S
authors.initials: YS
authors.lastname: Kivshar
authors.forename: Wieslaw
authors.initials: W
authors.lastname: Krolikowski