发表机构
Wrocław University of Science and Technology; University of Münster（弗罗茨瓦夫科技大学; 明斯特大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文通过有限元模拟和实验，研究了雪花型声子晶体腔与波导的耦合，发现耦合强度主要由空间模式重叠决定，并在GaAs薄膜中观察到约398 MHz的共振，为设计声子晶体器件提供了指导。
AI 中文摘要
声子晶体平台为实现可扩展的片上量子网络提供了一条有前景的路径，其中机械激发介导固态量子比特之间的相互作用。此类架构的一个关键构建模块是腔-波导系统，其中局域机械模式与传播的声子模式耦合。然而，对这种耦合机制进行定量理解仍不完整。在本工作中，我们利用有限元模拟和实验测量，研究了雪花型声子晶体腔的局域模式与声子晶体波导之间的相互作用。我们表明，耦合强度主要由相应的孤立腔和波导模式的位移场之间的空间重叠决定。在考虑归一化腔位移振幅的有效质量依赖性后，我们建立了在广泛的模式组合中空间重叠与相互作用强度之间的强相关性。偏离这种主导阶行为的情况与布洛赫相位效应、波导群速度的变化以及波导模式的内在杂化有关。此外，我们通过在GaAs声子晶体薄膜中观察到嵌入量子点的光致发光发射光谱展宽中的清晰共振，为腔-波导耦合提供了实验证据，该量子点作为机械场的局域探针。观察到的共振频率约为398 MHz，与有限元模拟预测的相应腔共振频率（约395 MHz）吻合良好。我们的结果确定了空间模式重叠作为腔-波导耦合的主导阶设计参数，并为控制声子晶体结构中局域模式与传播模式之间的相互作用提供了实用指南。
英文摘要
Phononic crystal platforms provide a promising route toward scalable on-chip quantum networks, where mechanical excitations mediate interactions between solid-state qubits. A key building block of such architectures is the cavity-waveguide system, in which localized mechanical modes couple to propagating phononic modes. However, a quantitative understanding of the mechanisms governing this coupling remains incomplete. In this work, we investigate the interaction between localized modes of snowflake-type phononic crystal cavities and a phononic crystal waveguide using finite-element simulations and experimental measurements. We show that the coupling strength is primarily governed by the spatial overlap between the displacement fields of the corresponding isolated cavity and waveguide modes. After accounting for the effective-mass dependence of the normalized cavity displacement amplitude, we establish a strong correlation between the spatial overlap and the interaction strength across a wide range of mode combinations. Deviations from this leading-order behavior are associated with Bloch-phase effects, variations in waveguide group velocity, and intrinsic hybridization of waveguide modes. Furthermore, we provide experimental evidence for cavity-waveguide coupling in a GaAs phononic crystal membrane by observing a clear resonance in the spectral broadening of the photoluminescence emission from an embedded quantum dot, which serves as a local probe of the mechanical field. The observed resonance at approximately 398 MHz is in good agreement with the corresponding cavity resonance near 395 MHz predicted by finite-element simulations. Our results identify spatial mode overlap as a leading-order design parameter for cavity-waveguide coupling and provide practical guidelines for controlling interactions between localized and propagating modes in phononic crystal structures.
Comments16 pages, 12 figures
