Non-Hermitian Delocalization in a Two-Dimensional Photonic Quasicrystal
Zhaoyang Zhang, Shun Liang, I. Septembre, Jiawei Yu, Yongping Huang, Maochang Liu, Yanpeng Zhang, Min Xiao, G. Malpuech, D. D. Solnyshkov
Abstract
Theoretical and experimental studies suggest that both Hermitian and non-Hermitian quasicrystals show localization due to the fractal spectrum and to the transition to diffusive bands via exceptional points, respectively. Here, we present an experimental study of a dodecagonal photonic quasicrystal based on electromagnetically induced transparency in a Rb vapor cell. First, we observe the suppression of the wave packet expansion in the Hermitian case. We then discover a new regime, where increasing the non-Hermiticity leads to delocalization, demonstrating that the behavior in non-Hermitian quasicrystals is richer than previously thought.