Observation of localized ground and excited orbitals in graphene photonic ribbons

Abstract

We report on the experimental realization of a quasi-one-dimensional photonic graphene ribbon supporting four flat-bands (FBs). We study the dynamics of fundamental and dipolar modes, which are analogous to the s and p orbitals, respectively. In the experiment, both modes (orbitals) are effectively decoupled from each other, implying two sets of six bands, where two of them are completely flat (dispersionless). Using an image generator setup, we excite the s and p FB modes and demonstrate their non-diffracting propagation for the first time. Our results open an exciting route towards photonic emulation of higher orbital dynamics.

Artificial flat band systems: from lattice models to experiments

“…Since then, several further experiments have been reported in various lattices [43,[148][149][150][151][152][153][154], studying quasi-1D flat bands [43,148], flat bands induced by periodic driving [150][151][152], forming optical logic gates out of CLS [153], and using superlattice structures to minimize the detrimental effect of next-nearest neighbour coupling on the band flatness [149,154].…”

Perfect localization on flat-band binary one-dimensional photonic lattices

“…V. ∆β = 0 LIMIT Although the case ∆β = 0 corresponds to a nonphysical solution in our photonic system [19,44,45], it becomes interesting to analyze it due to its phenomenology. By applying this condition, the eigenvalue problem (2) gives four simple solutions:…”

Singular flat bands

“…In the photonic lattice set-up, one can have more freedom to design lattice models, control band parameters of them, and prepare an initial state compared with the conventional condensed matter experiments. As a result, many flat band systems such as the Lieb [58][59][60][61] and kagome lattice models [62][63][64] have been studied by using the photonic lattice experimental set-ups [65][66][67][68][69][70][71].…”

“…In particular, the twisted bilayer graphene at the magic angle [46] has attracted a great attention due to its unconventional superconductivity [36,[47][48][49][50][51][52][53][54][55][56][57] and Mott insulating phases [36]. Furthermore, in artificial systems, such as the photonic lattices [58][59][60][61][62][63][64][65][66][67][68][69][70][71], cold atom systems [72,73], engineered atomic lattices [74], and metamaterials [75][76][77][78][79], one can have more controllability of the system parameters than the fermionic systems, and indeed almost flat bands were realized.…”