Photonic analogs of the moirésuperlattices mediated by interlayer electromagnetic coupling are expected to give rise to rich phenomena,such as nontrivial flatband topology.Here,we propose and demonstrate a scheme...Photonic analogs of the moirésuperlattices mediated by interlayer electromagnetic coupling are expected to give rise to rich phenomena,such as nontrivial flatband topology.Here,we propose and demonstrate a scheme to tune the flatbands in a bilayer moirésuperlattice by employing a band offset.The band offset is changed by fixing the bands of one slab while shifting those of the other slab,which is accomplished by modifying the thickness of the latter slab.Our results show that the band-offset tuning not only makes some flatbands emerge and disappear but also leads to two sets of flatbands that are robustly formed even with the change of band offset over a broad range.These robust flatbands form either at the AA-stack site or at the AB-stack site,and as a result,a single-cell superlattice can support a pair of high-quality localized modes with tunable frequencies.Moreover,we develop a diagrammatic model to provide an intuitive insight into the formation of the robust flatbands.Our work demonstrates a simple yet efficient way to design and control complex moiréflatbands,providing new opportunities to utilize photonic moirésuperlattices for advanced light–matter interaction,including lasing and nonlinear harmonic generation.展开更多
基金supported by Sichuan Science and Technology Program(2023NSFSC0460)the Fundamental Research Funds for the Central Universities(Grant No.ZYGX2020J010)+3 种基金the Open Project Funding of the Ministry of Education Key Laboratory of Weak-Light Nonlinear Photonics(Grant No.OS22-1)the Guangxi Natural Science Foundation(Grant No.2020GXNSFAA297041)the National Key R&D Program of China(Grant No.2022YFA1404800)the National Natural Science Foundation of China(Grant No.12134006).
文摘Photonic analogs of the moirésuperlattices mediated by interlayer electromagnetic coupling are expected to give rise to rich phenomena,such as nontrivial flatband topology.Here,we propose and demonstrate a scheme to tune the flatbands in a bilayer moirésuperlattice by employing a band offset.The band offset is changed by fixing the bands of one slab while shifting those of the other slab,which is accomplished by modifying the thickness of the latter slab.Our results show that the band-offset tuning not only makes some flatbands emerge and disappear but also leads to two sets of flatbands that are robustly formed even with the change of band offset over a broad range.These robust flatbands form either at the AA-stack site or at the AB-stack site,and as a result,a single-cell superlattice can support a pair of high-quality localized modes with tunable frequencies.Moreover,we develop a diagrammatic model to provide an intuitive insight into the formation of the robust flatbands.Our work demonstrates a simple yet efficient way to design and control complex moiréflatbands,providing new opportunities to utilize photonic moirésuperlattices for advanced light–matter interaction,including lasing and nonlinear harmonic generation.
