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Parity–time synthetic photonic lattices


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.

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Figure 1: PT-symmetric fibre networks.
Figure 2: Band structure and measured single-pulse evolution in the PT synthetic network.
Figure 3: Exploring the PT threshold of a lattice using a two-parameter scan.
Figure 4: Bloch oscillations (experiment) and superluminal energy transport (simulation).
Figure 5: Experimentally observed unidirectional invisibility of PT-symmetric Bragg scatterers.


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We acknowledge financial support from DFG Forschergruppe 760, the Cluster of Excellence Engineering of Advanced Materials, SAOT and the German-Israeli Foundation. This work was also supported by NSF grant ECCS-1128520 and by AFOSR grant FA95501210148. Moreover, we thank J. Näger for technical support.

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All authors contributed extensively to the work presented in this paper.

Corresponding authors

Correspondence to Demetrios N. Christodoulides or Ulf Peschel.

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The authors declare no competing financial interests.

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Regensburger, A., Bersch, C., Miri, MA. et al. Parity–time synthetic photonic lattices. Nature 488, 167–171 (2012).

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