Observation of Defect States in $\mathsc{P}\mathsc{T}$-Symmetric Optical Lattices

Observation of Defect States in $P T$ -Symmetric Optical Lattices

Alois Regensburger, Mohammad-Ali Miri, Christoph Bersch, Jakob Näger, Georgy Onishchukov, Demetrios N. Christodoulides, and Ulf Peschel

Phys. Rev. Lett. 110, 223902 – Published 29 May 2013

Abstract

We provide the first experimental demonstration of defect states in parity-time ( $P T$ ) symmetric mesh-periodic potentials. Our results indicate that these localized modes can undergo an abrupt phase transition in spite of the fact that they remain localized in a $P T$ -symmetric periodic environment. Even more intriguing is the possibility of observing a linearly growing radiation emission from such defects provided their eigenvalue is associated with an exceptional point that resides within the continuum part of the spectrum. Localized complex modes existing outside the band-gap regions are also reported along with their evolution dynamics.

Received 14 November 2012

DOI:https://doi.org/10.1103/PhysRevLett.110.223902

Authors & Affiliations

Alois Regensburger¹, Mohammad-Ali Miri², Christoph Bersch¹, Jakob Näger¹, Georgy Onishchukov³, Demetrios N. Christodoulides², and Ulf Peschel^1,*

¹Institute of Optics, Information, and Photonics, SAOT, University of Erlangen-Nuernberg, 91058 Erlangen, Germany
²CREOL/College of Optics, University of Central Florida, Orlando, Florida 32816, USA
³Max Planck Institute for the Science of Light, 91058 Erlangen, Germany