Inhomogeneous uniaxial strain-induced lattice deformations result in the Dirac point shift,leading to a strong synthetic pseudomagnetic field.The chiral edge state in the Haldane model and the antichiral edge state in...Inhomogeneous uniaxial strain-induced lattice deformations result in the Dirac point shift,leading to a strong synthetic pseudomagnetic field.The chiral edge state in the Haldane model and the antichiral edge state in the modified Haldanemodel can be realized in gyromagnetic photonic crystals,immersed in external real magnetic fields.Here,the interplay of the real-and pseudo-magnetic fields is investigated based on the onsite magnetization modulation and the uniaxial strain within gyromagnetic photonic crystals,thereby resulting in photonic band deformations including the shift of the chiral edge states and the lift of the degenerate antichiral edge states.The experiment is further performed to observe the imbalanced transport of these edge states on two opposite sides.Our findings can help to deeply explore rich and significant physics of synthetic gauge fields,and facilitate designs of photonic functional devices,such as the proposed unidirectional multichannel waveguide.展开更多
Pseudomagnetic fields(PMFs)can manipulate photons in a similar way that magnetic fields control electrons.However,the PMF-based control over light has been restricted to simple waveguiding of the Landau level states,w...Pseudomagnetic fields(PMFs)can manipulate photons in a similar way that magnetic fields control electrons.However,the PMF-based control over light has been restricted to simple waveguiding of the Landau level states,which hinders the application of PMFs in practical photonic integrated circuits.Here,we propose a universal and systematic methodology to design complex nonuniform PMFs and arbitrarily control the flow of light in silicon photonic crystals at telecommunication wavelengths.As proofs of concept,an S-bend(with a low insertion loss of<1.83 dB)and a 50:50 power splitter(with a low excess loss of<2.11 dB and imbalance of less than±0.5 dB)based on PMFs are experimentally demonstrated.A high-speed data transmission experiment is performed on these devices with 140-Gb∕s four-level pulse amplitude modulation signals to prove their applicability in real communication systems.The proposed method offers a paradigm for exploring magnetic-field-related physics with neutral particles and developing nanophotonic devices with PMF-induced states beyond the Landau level states and the topological edge states.展开更多
While conventional topological states can be used for robust acoustic energy transportation,the energy capacity is limited and the propagation route is also heavily constrained.In this work,we show that Landau levels ...While conventional topological states can be used for robust acoustic energy transportation,the energy capacity is limited and the propagation route is also heavily constrained.In this work,we show that Landau levels in acoustic systems can offer exciting new avenues for transporting acoustic energies.In particular,we realize valley-dependent Landau levels in a two-dimensional inhomogeneous acoustic system induced by synthetic in-plane magnetic fields.The band diagrams of the 0th-and 1st-order Landau levels are experimentally measured and their robustness of propagation against defects is also experimentally validated.Promising ways for acoustic energy transportation enabled by the Landau levels,such as large-area transportation and snake-like transportation are experimentally demonstrated.Importantly,we achieve topological propagation along an arbitrary prescribed path using unique features of the valley-dependent Landau levels for the first time in experiment,which is a significant advancement beyond what can be achieved using conventional acoustic topological states based on valley/spin Hall physics.These remarkable features open up promising opportunities for developing novel acoustic devices to realize robust,broadband,and flexible large-area acoustic energy conveying.展开更多
It has recently been shown that the non-Hermitian skin effect can be suppressed by magnetic fields. In this work, using a two-dimensional tight-binding lattice, we demonstrate that a pseudomagnetic field can also lead...It has recently been shown that the non-Hermitian skin effect can be suppressed by magnetic fields. In this work, using a two-dimensional tight-binding lattice, we demonstrate that a pseudomagnetic field can also lead to the suppression of the non-Hermitian skin effect. With an increasing pseudomagnetic field, the skin modes are found to be pushed into the bulk, accompanied by the reduction of skin topological area and the restoration of Landau level energies. Our results provide a time-reversal invariant route to localization control and could be useful in various classical wave devices that are able to host the non-Hermitian skin effect but inert to magnetic fields.展开更多
基金Fundamental Research Funds for the Central Universities(2023ZDYQ11003)National Natural Science Foundation of China(12274315,52227901)+1 种基金China Postdoctoral Science Foundation(2023M743784)State Key Laboratory of Millimeter Waves(K202407)。
文摘Inhomogeneous uniaxial strain-induced lattice deformations result in the Dirac point shift,leading to a strong synthetic pseudomagnetic field.The chiral edge state in the Haldane model and the antichiral edge state in the modified Haldanemodel can be realized in gyromagnetic photonic crystals,immersed in external real magnetic fields.Here,the interplay of the real-and pseudo-magnetic fields is investigated based on the onsite magnetization modulation and the uniaxial strain within gyromagnetic photonic crystals,thereby resulting in photonic band deformations including the shift of the chiral edge states and the lift of the degenerate antichiral edge states.The experiment is further performed to observe the imbalanced transport of these edge states on two opposite sides.Our findings can help to deeply explore rich and significant physics of synthetic gauge fields,and facilitate designs of photonic functional devices,such as the proposed unidirectional multichannel waveguide.
基金supported in part by the National Key Research and Development Program of China[Grant No.2023YFB2905503(L.S.)]the National Natural Science Foundation of China[Grant Nos.62035016(J.D.),62475146(L.S.),62105200(L.S.),and 62341508(Y.S.)].
文摘Pseudomagnetic fields(PMFs)can manipulate photons in a similar way that magnetic fields control electrons.However,the PMF-based control over light has been restricted to simple waveguiding of the Landau level states,which hinders the application of PMFs in practical photonic integrated circuits.Here,we propose a universal and systematic methodology to design complex nonuniform PMFs and arbitrarily control the flow of light in silicon photonic crystals at telecommunication wavelengths.As proofs of concept,an S-bend(with a low insertion loss of<1.83 dB)and a 50:50 power splitter(with a low excess loss of<2.11 dB and imbalance of less than±0.5 dB)based on PMFs are experimentally demonstrated.A high-speed data transmission experiment is performed on these devices with 140-Gb∕s four-level pulse amplitude modulation signals to prove their applicability in real communication systems.The proposed method offers a paradigm for exploring magnetic-field-related physics with neutral particles and developing nanophotonic devices with PMF-induced states beyond the Landau level states and the topological edge states.
基金supported by the University-Industry Collaborative Education Program of the Ministry of Education of China(Grant No.220804972162224)the National Natural Science Foundation of China(Grant Nos.92263208 and 12102134)+3 种基金the National Key R&D Program of China(Grant Nos.2022YFA1404400 and 2022YFA1404403)the Fundamental Research Funds for the Central Universities,the Research Grants Council of Hong Kong SAR(Grant Nos.15214323,15200922,15202820,and AoE/P-502/20)the Hong Kong Innovation and Technology Commission via project“Smart Railway Technology and Applications”(Grant No.K-BBY1)the Faculty Development Scheme(FDS)RGC Project(Grant No.UGC/FDS24/E04/21).
文摘While conventional topological states can be used for robust acoustic energy transportation,the energy capacity is limited and the propagation route is also heavily constrained.In this work,we show that Landau levels in acoustic systems can offer exciting new avenues for transporting acoustic energies.In particular,we realize valley-dependent Landau levels in a two-dimensional inhomogeneous acoustic system induced by synthetic in-plane magnetic fields.The band diagrams of the 0th-and 1st-order Landau levels are experimentally measured and their robustness of propagation against defects is also experimentally validated.Promising ways for acoustic energy transportation enabled by the Landau levels,such as large-area transportation and snake-like transportation are experimentally demonstrated.Importantly,we achieve topological propagation along an arbitrary prescribed path using unique features of the valley-dependent Landau levels for the first time in experiment,which is a significant advancement beyond what can be achieved using conventional acoustic topological states based on valley/spin Hall physics.These remarkable features open up promising opportunities for developing novel acoustic devices to realize robust,broadband,and flexible large-area acoustic energy conveying.
基金supported by National Research Foundation Singapore Competitive Research Program (NRF-CRP232019-0007)support from the start-up fund and the direct grant (4053675) of The Chinese University of Hong Kong。
文摘It has recently been shown that the non-Hermitian skin effect can be suppressed by magnetic fields. In this work, using a two-dimensional tight-binding lattice, we demonstrate that a pseudomagnetic field can also lead to the suppression of the non-Hermitian skin effect. With an increasing pseudomagnetic field, the skin modes are found to be pushed into the bulk, accompanied by the reduction of skin topological area and the restoration of Landau level energies. Our results provide a time-reversal invariant route to localization control and could be useful in various classical wave devices that are able to host the non-Hermitian skin effect but inert to magnetic fields.
