Institute of Optics, Information, and Photonics, SAOT, University of Erlangen-Nuernberg, 91058 Erlangen, Germany.
Phys Rev Lett. 2013 May 31;110(22):223902. doi: 10.1103/PhysRevLett.110.223902. Epub 2013 May 29.
We provide the first experimental demonstration of defect states in parity-time (PT) 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 PT-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.
我们提供了在宇称时间（PT）对称网格周期势中缺陷态的首个实验演示。我们的结果表明，尽管这些局域模式存在于 PT 对称周期环境中，但它们仍能经历突然的相位转变。更有趣的是，如果它们的本征值与位于谱连续部分的异常点相关，那么可以观察到这种缺陷的线性辐射发射。我们还报告了存在于带隙区域之外的局域复模态及其演化动力学。
