摘要
近年来,在拓扑绝缘体理论体系的支撑下,拓扑光子学因具有独特的光场调控能力而引起了广泛关注,并发展出具有拓扑特性的拓扑光子器件.基于不同光学平台的拓扑光子器件具有高集成度、抗扰动、抗无序影响等优点,在光传感、光通信、光量子计算方面有广泛的应用前景.其中光波导阵列由于制备简单、结构精细,且结构的拓扑特性能通过光动力学可视化,是研究拓扑光子学的理想平台之一.本文主要以拓扑光子学理论为基础,对光波导阵列中不同维度的拓扑光子学模型及其实验进展进行回顾与总结,并对拓扑光波导阵列器件制备的难点、发展趋势等进行展望.
Abstract
Topological insulators have been a novel area of research since the integer quantum Hall effect was proposed.The concept of topology was soon introduced to the field of photonics and attracted a lot of research attention due to the unique ability of light manipulation.Research on topological edge states,Anderson localization,and other interesting topological properties have been conducted in different systems.Topological photonic insulators,constructed on various platforms,have the advantages of high integration,robustness to external disorders under topological protection,and exhibit wide application prospects in light sensing,communications,and quantum computing.Optical waveguide arrays,with their properties of simple fabrication and fine structure,are one of the ideal platforms for studying topological photonics.Due to the similarity between the Schrodinger equation and the paraxial equation,topological properties can be visualized through light dynamics.In addition,a new type of Floquet topological insulator can be realized through space modulation in the z direction.In experiments,by changing the parameters of the waveguide arrays,such as refractive index,waveguide spacing,and waveguide configuration,the light field in waveguide arrays can be flexibly controlled within the tight-binding model.In addition,space modulation in the z direction and manipulation of non-Hermitian and nonlinear effects in waveguide arrays can realize novel topological photonic insulators.In this paper,we mainly focus on topological photonic insulators constructed using optical waveguide arrays and review recent experiments realized in different dimensions,covering the following aspects.First,we introduce the coupled-mode theory,which is the basis of topological photonics in waveguide arrays.We also describe the common fabrication methods of optical waveguide arrays,such as ultrafast laser direct writing and E-beam lithography,and we analyze the advantages and disadvantages of these methods.Second,some typical topological experiments in one and two dimensions are introduced,discussing the topological phase transition and the bulk-edge correspondence in different models based on waveguide arrays.Most of the experiments have been realized in straight waveguides;however,recent research has found that helical waveguides are also useful.The z-reversal symmetry of the system can be broken by changing the shape of the waveguide in the z direction,revealing new topological properties.Third,we review non-Hermitian effects in topological waveguide arrays.Non-Hermitian modulation can be achieved by introducing gain and loss in waveguides.In experiments,loss can be easily introduced through spatial modulation or artificial additional loss,while gain is more difficult to achieve.Finally,we discuss the application potential of topological photonic insulators in waveguide arrays.In short,topological photonic insulators with novel light control properties are one of the interesting branches of condensed matter physics,which has application potential in many fields.Through this review,we hope to gain a comprehensive understanding of topological photonics in optical waveguide arrays and inspire future applications in topological optical waveguide array devices.
基金项目
国家自然科学基金(12204179)
国家自然科学基金(62122027)
国家自然科学基金(52002128)
国家自然科学基金(62075063)
广东省自然科学基金(2022A1515011289)
广东省自然科学基金(2021A1515110475)
广州市基础与应用基础研究基金(202201010407)
NETL
NSTL
万方数据