El-Ganainy, Ramy Max Planck Institute for the Physics of Complex Systems, Max Planck Society;
https://www.nature.com/articles/s41566-017-0031-1 (Publisher version)
Feng, L., El-Ganainy, R., & Ge, L. (2017). Non-Hermitian photonics based on parity-time symmetry. Nature Photonics, 11(12), 752-762. doi:10.1038/s41566-017-0031-1.