Efficient and tunable photoinduced moiré lattice in an atomic ensemble

Photonic moiré lattices (PMLs), with unique twisted periodic patterns, provide a valuable platform for investigating strongly correlated materials, unconventional superconductivity, and the localization−delocalization transition. However, PMLs created either by the misorientation between lattice layers or by twisted van der Waals materials are typically non-tunable and inherently possess immutable refractive indices. Unlike those in the moiré lattices of twisted two-dimensional materials, our work reports a moiré lattice formed by overlapping two identical sublattices with twisted angles in an ultracold atomic ensemble. This photoinduced moiré lattice with two twisted sublattices exhibits high flexibility and rich periodicity through adjustable twisted angles. Our results indicate that both the absorption/dispersion coefficients and the transmission of the photoinduced moiré lattices can be effectively tuned by photon detuning and Rabi frequency, resulting in amplitude- and phase-type moiré lattices. Based on the Fraunhofer diffraction theory, we have demonstrated that the far-field diffraction efficiency can be adjusted via altering photon detuning, and the rotation angle serves as a control knob for modulating the diffracted intensity distribution, thereby optimizing the performance of the photonic lattice. It is also found that the operation domains of the moiré lattices with different rotation angles remain consistent, allowing for seamless conversion between various moiré period structures. Furthermore, a moiré lattice composed of three twisted sublattices is investigated, revealing that the diffraction energy is uniformly dispersed in a circular distribution, which provides excellent agility in the design of optical devices. Such tunable PML offer a powerful tool for studying light propagation control and the intriguing physics of twisted systems in atomic media.