English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Open

Presents the pdf analysis as premium feature

PDF Analysis

Insights

Presents the summarisation as premium feature

Summarisation

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

The evolution of a pair of resonant Bragg modes through a mediumcharacterized by a complex one-dimensional $\mathcal{PT}$-symmetric periodicpermittivity is thoroughly investigated. Analytic solutions of Maxwell'sequations are derived beyond the paraxial approximation to investigate theperiodic energy exchange that occurs between the Bragg modes for the Hermitianlattices as well as for complex lattices. Three regimes defined by the symmetrybreaking point are discussed: below it, above it and at it. These regimes aredetermined by the existence of four real eigenvalues in the symmetric phase,which collide and coalesce into a pair at the breaking point. Above thecritical value each member of the pair bifurcates into a pair of complexvalues. Therefore, the complex lattice reveals a variety of wave dynamicsdepending on the gain/loss balance. In all regimes of the transition thesignature of $\mathcal{PT}$-symmetric systems is present, as the evolution isalways nonreciprocal and unidirectional.

Nonparaxial electromagnetic Bragg scattering in periodic media with PT symmetry