Brasselet, EtienneMiroshnichenko, AndreyKivshar, Yuri2015-12-162015-12-160003-6951http://hdl.handle.net/1885/95071We demonstrate how to achieve reversible nonreciprocal optical response in a periodic photonic structure with a pair of defects, one of them being a nonlinear liquid crystal defect layer. The twin defect layers structure is symmetric at low intensity and becomes asymmetric above a power threshold corresponding to the optical reordering of the liquid crystal. We show that nonreciprocal effects can be reversed by changing the wavelength as a consequence of the defect mode dependent light localization inside the structure.The work has been supported by the Australian Research Council project DP0771218 and the the France-Australia cooperation project 21337 of CNRS.http://www.sherpa.ac.uk/romeo/issn/0003-6951..."Publishers version/PDF may be used on author's personal website, institutional website or institutional repository" from SHERPA/RoMEO site (as at 17/12/15). Copyright 2010 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters and may be found at https://doi.org/10.1063/1.3300824Keywords: Defect layers; Defect mode; Intensity threshold; Light localization; Low-intensity; Nonlinear liquids; Nonreciprocal; Nonreciprocity; Optical response; Photonic structure; Crystal defects; Crystal structure; Liquid crystals; Periodic structures2010-02-1010.1063/1.33008242016-02-24