Centre de Nanosciences et de Nanotechnologies (C2N), CNRS, Université Paris-Sud, Université Paris-Saclay, 91120 Palaiseau, France.
Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Stadionallee 2, 1020 Vienna, Austria.
Phys Rev Lett. 2019 Sep 13;123(11):113901. doi: 10.1103/PhysRevLett.123.113901.
Phase frustration in periodic lattices is responsible for the formation of dispersionless flatbands. The absence of any kinetic energy scale makes flatband physics critically sensitive to perturbations and interactions. We report on the experimental investigation of the nonlinear response of cavity polaritons in the gapped flatband of a one-dimensional Lieb lattice. We observe the formation of gap solitons with quantized size and abrupt edges, a signature of the frozen propagation of switching fronts. This type of gap soliton belongs to the class of truncated Bloch waves, and has only been observed in closed systems up to now. Here, the driven-dissipative character of the system gives rise to a complex multistability of the flatband nonlinear domains. These results open up an interesting perspective regarding more complex 2D lattices and the generation of correlated photon phases.
周期性晶格中的位相失谐导致无弥散的扁平能带的形成。由于不存在任何动能尺度，扁平带物理对微扰和相互作用非常敏感。我们报告了在一维李（Lieb）晶格的带隙扁平带中腔极化激元的非线性响应的实验研究。我们观察到具有量化大小和突然边缘的间隙孤子的形成，这是开关前沿冻结传播的特征。这种类型的间隙孤子属于截断布洛赫波的一类，迄今为止仅在封闭系统中观察到。在这里，系统的驱动耗散特性导致扁平带非线性域的复杂多稳定性。这些结果为更复杂的二维晶格和相关光子相位的产生开辟了一个有趣的视角。
