Nonlocality in PT -symmetric waveguide arrays with gain and loss

Abstract

We demonstrate that light propagation in waveguide arrays that include PT -symmetric structures can exhibit strongly nonlocal sensitivity to topology of the array at fixed other parameters. We consider an array composed of lossless waveguides, that includes a pair of PT -symmetric waveguides with balanced gain and loss, and reveal that PT -symmetry breaking thresholds are different for planar and circular array configurations. These results demonstrate that PT -symmetric structures can offer new regimes for optical beam shaping compared to conservative structures.