Institute of Spectroscopy, Russian Academy of Sciences, 108840 Troitsk, Moscow, Russia.
Faculty of Physics, Higher School of Economics, 105066 Moscow, Russia.
Phys Rev Lett. 2023 Feb 24;130(8):083801. doi: 10.1103/PhysRevLett.130.083801.
We observe linear and nonlinear light localization at the edges and in the corners of truncated moiré arrays created by the superposition of periodic mutually twisted at Pythagorean angles square sublattices. Experimentally exciting corner linear modes in the femtosecond-laser written moiré arrays we find drastic differences in their localization properties in comparison with the bulk excitations. We also address the impact of nonlinearity on the corner and bulk modes and experimentally observe the crossover from linear quasilocalized states to the surface solitons emerging at the higher input powers. Our results constitute the first experimental demonstration of localization phenomena induced by truncation of periodic moiré structures in photonic systems.
我们观察到在由周期性相互扭曲成毕达哥拉斯角的正方形亚晶格叠加而成的截断莫尔阵列的边缘和角处的线性和非线性光局域现象。通过在飞秒激光写入的莫尔阵列中激发角线性模式，我们发现与体激发相比，它们的局域性质有很大的差异。我们还研究了非线性对角和体模式的影响，并实验观察到从线性准局域态到在更高输入功率下出现的表面孤子的转变。我们的结果首次实验证明了在光子系统中由周期性莫尔结构的截断引起的局域化现象。
