We introduce a novel concept of the {\em pseudo} parity-time (\(\mathcal{PT}\)) symmetry in periodically modulated optical systems with balanced gain and loss. We demonstrate that whether the original system is \(\mathcal{PT}\)-symmetric or not, we can manipulate the property of the \(\mathcal{PT}\) symmetry by applying a periodic modulation in such a way that the effective system derived by the high-frequency Floquet method is \(\mathcal{PT}\) symmetric. If the original system is non-\(\mathcal{PT}\) symmetric, the \(\mathcal{PT}\) symmetry in the effective system will lead to quasi-stationary propagation that can be associated with the \emph{pseudo \(\mathcal{PT}\) symmetry}. Our results provide a promising approach for manipulating the \(\mathcal{PT}\) symmetry of realistic systems.

http://arxiv.org/abs/1302.1091
Optics (physics.optics); Quantum Physics (quant-ph)