Phase Transition in PT Symmetric Active Plasmonic Systems

Artículo de publicación ISISurface plasmon polaritons (SPPs) are coherent electromagnetic surface waves trapped on an insulator-conductor interface. The SPPs decay exponentially along the propagation due to conductor losses, restricting the SPPs propagation length to few microns. Gain materials can be used to counterbalance the aforementioned losses. We provide an exact expression for the gain, in terms of the optical properties of the interface, for which the losses are eliminated. In addition, we show that systems characterized by lossless SPP propagation are related to PT symmetric systems. Furthermore, we derive an analytical critical value of the gain describing a phase transition between lossless and prohibited SPPs propagation. The regime of the aforementioned propagation can be directed by the optical properties of the system under scrutiny. Finally, we perform COMSOL simulations verifying the theoretical findings.European Union FP7-REGPOT-2012-2013-1 316165 Fondecyt 1120123 ICM P10-030-F Programa de Financiamiento Basal de CONICYT FB0824/2008 Ministry of Education and Science of the Republic of Kazakhstan 339/76-2015 Ministry of Education and Science of the Russian Federation K2-2015-00