Non-Hermitian twisted photonic lattices

Twisted photonic lattices have recently emerged as a promising platform for opto-twistronics, enabling the exploration of moiré-induced photonic phenomena. Despite significant progress, the implications of non-Hermitian effects within these systems remain largely unexplored. In this work, we theoretically propose and experimentally demonstrate a non-Hermitian twisted photonic lattice with dynamically tunable gain-loss modulation, realized in a four-level atomic medium through the twisted superposition of two stripe fields. By adjusting the frequency detuning, a local flat band is introduced into the photonic band structure, leading to the directional localization of light in momentum space. The degree of localization can be further controlled by varying the laser power, while the direction of localization is reconfigured in real time by tuning the twist angle. Our work uncovers an intriguing interplay between non-Hermitian band reconstruction and geometric twisting by means of reconfigurable photonic lattice, and it provides a versatile platform for studying light manipulation in twisted configurations.