title: Parity-time synthetic photonic lattices.
abstract: The development of new artificial structures and materials is today one of the major research challenges in optics. In most studies so far, the design of such structures has been based on the judicious manipulation of their refractive index properties. Recently, the prospect of simultaneously using gain and loss was suggested as a new way of achieving optical behaviour that is at present unattainable with standard arrangements. What facilitated these quests is the recently developed notion of 'parity-time symmetry' in optical systems, which allows a controlled interplay between gain and loss. Here we report the experimental observation of light transport in large-scale temporal lattices that are parity-time symmetric. In addition, we demonstrate that periodic structures respecting this symmetry can act as unidirectional invisible media when operated near their exceptional points. Our experimental results represent a step in the application of concepts from parity-time symmetry to a new generation of multifunctional optical devices and networks.
authors.affiliation: Institute of Optics, Information and Photonics, University of Erlangen-Nürnberg, Staudtstraße 7/B2, 91058 Erlangen, Germany.
authors.forename: Alois
authors.initials: A
authors.lastname: Regensburger
authors.forename: Christoph
authors.initials: C
authors.lastname: Bersch
authors.forename: Mohammad-Ali
authors.initials: MA
authors.lastname: Miri
authors.forename: Georgy
authors.initials: G
authors.lastname: Onishchukov
authors.forename: Demetrios N
authors.initials: DN
authors.lastname: Christodoulides
authors.forename: Ulf
authors.initials: U
authors.lastname: Peschel