摘要
在经典波系统中,赝磁场作为人工合成的规范场,可以像真实磁场一样调控波的传输,从而受到了人们的广泛关注.本文利用在二维光子晶体中引入单向线性梯度形变的方式,构建空间均匀分布的赝磁场.强赝磁场的存在导致光子晶体出现朗道能级量子化.与真实磁场不同,光子晶体赝磁场在两个不等价的能谷中相反,系统的时间反演对称性没有被打破.设计的光子晶体支持边界态的输运,并且能够使波束的传输路径发生弯曲.将具有相反赝磁场的光子晶体构造在一起还能够实现有趣的“蛇态”传输,为操控电磁波的传输并设计信息处理器件提供了良好的平台.
Many interesting phenomena,such as quantization of Landau levels and quantum Hall effect,can occur in an electronic system under a strong magnetic field.However,photons do not carry charge,and they do not have many properties induced by external magnetic fields,either.Recently,the pseudomagnetic field,an artificial synthetic gauge field,has attracted intense research interest in classical wave systems,in which the propagation of the wave can be manipulated like in a real magnetic field.The photonic crystal is an optical structure composed of periodic material distributions and provides a good platform for studying the control of electromagnetic waves.In this work,we construct a uniform pseudomagnetic field by introducing uniaxial linear gradient deformation of metallic rods in a two-dimensional photonic crystal.The strong pseudomagnetic field leads to the quantization of photonic Landau levels in photonic crystal.The sublattice polarization of n=0 Landau level is also demonstrated in our simulations.Unlike the real magnetic field,the pseudomagnetic fields of photonic crystal is opposite in two inequivalent energy valleys,and the time-reversal symmetry of the system is not broken.Our designed gradient photonic crystals support the transport of edge state in the gap between n=0 and n=±1 Landau levels.The edge state can propagate unidirectionally when it is excited by a chiral source.When a gaussian beam impinges on the photonic crystal,the propagating paths of two splitting beams can be controlled,which gives rise to the bend of two beams.Two photonic crystals with opposite pseudomagnetic fields are assembled together,and the interesting phenomenon of“snake-state”can be obtained.Our proposal opens the way for designing information processing devices by manipulating electromagnetic waves.
作者
杨玉婷
钱欣悦
石礼伟
Yang Yu-Ting;Qian Xin-Yue;Shi Li-Wei(School of Materials Science and Physics,China University of Mining and Technology,Xuzhou 221116,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2023年第13期95-102,共8页
Acta Physica Sinica
基金
国家自然科学基金(批准号:12004425)
江苏省自然科学基金(批准号:BK20200630)
徐州市基础研究计划(批准号:KC22016)
中国矿业大学重点学科经费(批准号:2022WLXK06)
江苏省青蓝工程资助的课题。
关键词
光子晶体
赝磁场
朗道能级
边界态
photonic crystal
pseudomagnetic field
Landau level
edge state