Type-I Weyl points induced by negative coupling in photonic crystal
Type-I Weyl points induced by negative coupling in photonic crystal作者机构:Beijing Engineering Research Center of Mixed Reality and Advanced DisplaySchool of Oprics and PhotonicsBeijing Instirute of TechnologyBeijing 100081China
出 版 物:《Science China(Physics,Mechanics & Astronomy)》 (中国科学:物理学、力学、天文学(英文版))
年 卷 期:2021年第64卷第6期
页 面:66-73页
核心收录:
基 金:supported by the Beijing Outstanding Young Scientist Program(Grant No.BJJWZYJH01201910007022) the National Natural Science Foundation of China(Grant Nos.61775019,and 92050117) the National Postdoctoral Program for Innovative Talents of China(Grant No.BX20200050)
主 题:topological photonics Weyl semimetal photonic crystal
摘 要:Weyl points,which are the degenerate points in three-dimensional momentum space,have been widely studied in the photonic system,and show some intriguing phenomena such as topologically protected surface states and chiral ***-I Weyl systems possess a complete bandgap,and topologically protected surface states can be excited without disturbing the bulk *** this work,we investigate the influence of the sign of coupling coefficient on the topological property of the system and find that type-I Weyl points can be realized by introducing a negative coupling between the stacking layers of the designed photonic *** propose a new strategy to construct a type-I Weyl system by stacking the hexagonal photonic *** from the topological nontrivial photonic system with a positive coefficient,the negative couplings in the photonic system are realized by adding another resonating site between stacking *** theoretically demonstrate that the effective coupling between the resonating sites in adjacent layers sign-flips through the judicious design of the nearest coupling strength and eigenfrequency of the additional *** surface states at opposite boundaries of the proposed system have opposite group velocities,which is the feature of type-I Weyl *** study provides a new method of exploring topologically protected photonic systems and developing possible topological devices.