Unidirectional Invisibility induced by PT-Symmetric Periodic Structures

TL;DR

This paper demonstrates that PT-symmetric periodic structures can achieve unidirectional invisibility near the symmetry breaking point, with potential applications in optical devices.

Contribution

It introduces a novel mechanism for unidirectional invisibility using PT-symmetric Bragg structures near the symmetry breaking point.

Findings

Reflection is suppressed from one side while enhanced from the other.

Transmission and phase are unaffected, mimicking an invisible medium.

The effect persists even with Kerr nonlinearities and can suppress optical bistabilities.

Abstract

We show that parity-time (PT) symmetric Bragg periodic structures, near the spontaneous PT - symmetry breaking point, can act as unidirectional invisible media. In this regime, the re flection from one end is diminished while it is enhanced from the other. At the same time the transmission coefficient and phase, are indistinguishable from those expected in the absence of a grating. The phenomenon is robust even in the presence of Kerr non-linearities, and it can also effectively suppress optical bistabilities.