光子晶体纳米梁腔-波导耦合系统中的单向无反射现象研究  

Unidirectional reflectionless propagation in a photonic crystal nanobeam cavity-waveguide coupled system

作　　者：江一帆 邓超笙 JIANG Yifan;DENG Chaosheng(School of Physics and Optoelectronics,Xiangtan University,Xiangtan 411105,China)

机构地区：[1]湘潭大学物理与光电工程学院,湖南湘潭411105

出　　处：《湘潭大学学报(自然科学版)》2025年第1期66-73,共8页Journal of Xiangtan University(Natural Science Edition)

摘　　要：基于具有宇称-时间对称的非厄米哈密顿系统,对光子晶体纳米梁腔-波导间接耦合系统的反射特性进行研究.通过对两个光子晶体纳米梁腔中心距离的调制,深入研究了光子晶体纳米梁腔-波导间接耦合系统中的非互易传输效应.结果表明,中心距离的变化会导致相位的改变,最终成功找到了两个奇异点.在奇异点处,可以观察到单向无反射现象,成功实现了光在系统中的非互易传输.利用理论计算奇异点处的系统本征值,本征值的合并证明了奇异点处发生了宇称-时间对称的破缺,实现了从互易到非互易的转换,同时两个奇异点附近,光的吸收率接近0.75.这项研究为未来开发滤波器、光隔离器和光传感器等集成光子器件展示了巨大的前景.Based on a non-Hermitian system with parity-time symmetry,the reflection characteristics of photonic crystal nanobeam cavity-waveguide indirect coupling system are studied.By properly adjusting the lateral distance between the two photonic crystal nanobeam cavities,the non-reciprocal transmission in the indirect coupling system is deeply investigated.The results show that two exceptional points are successfully found due to the phase shifts caused by the change of lateral distance.At the EPs,unidirectional reflectionless phenomenon can be observed,and the non-reciprocal transmission of light in the system is realized successfully.The eigenvalues of the system at the EPs are calculated theoretically.The emerge of the eigenvalues proves that the PT symmetry is broken,and the conversion from reciprocity to non-reciprocity is realized.At the same time,near two points that the absorption is near 0.75.The research shows huge prospects for developing integrated photonic circuits like filters,optical isolators,and sensors.

关 键 词：光子晶体纳米梁腔 单向无反射现象 奇异点 宇称-时间对称破缺 非互易传输 

分 类 号：O734[理学—晶体学]