设计一种包含顶角经过圆角处理的金属脊和特定三角形空气间隙层的混合表面等离子激元波导结构, 这种特定三角形结构和其他材料的组合有效提高了纳米激光器的性能。应用有限元法, 借助于COMSOL Multiphysics软件分别构建二维平面和三维体积模型, 使用模态分析模块对该波导结构的波导特性与激光器特性进行分析。结果表明, 当工作波长为1550 nm时, 所设计波导的光场约束可以达到较好的亚深波长水平, 同时保持较大的传输长度。该波导结构可以实现表面等离子体激元模式和纳米线模式之间的超强耦合, 耦合强度最高可以达到0.96, 传播长度可以达到28047 nm。将该结构应用于激光器, 通过调整波导设计参数获得了高质量因子、低能量损耗、低阈值极限、超小的有效模式体积。与单一三角形空气间隙结构相比, 在相同的参数下, 所设计的结构具有更强的光场限制能力和微腔束缚能力。该结构有望应用于片上互连、光子集成电路、光学存储、光信号处理等领域。

We propose a hybrid surface plasmonic waveguide structure containing a metal ridge with rounded corners and a special triangular air gap layer. The combination of this particular triangular structure and other materials effectively improves the performance of nano-lasers. We apply the finite element method and use COMSOL Multiphysics software to construct the two-dimensional and three-dimensional models, and use the modal analysis module to analyze the waveguide characteristics of the waveguide structure and the parameters of the laser. The results indicate that the optical field confinement of the designed waveguide can reach a better deep-subwavelength level while maintaining a long propagation length at the 1550 nm operating wavelength. The waveguide structure enables super strong coupling between the surface plasmon polariton mode and the cylindrical mode. The maximum coupling strength is 0.96 and the propagation length is 28047 nm. When this structure is applied to nano-lasers, we adjust the waveguide design parameters to obtain the higher quality factor, lower energy loss, threshold limit, and ultra-small effective mode size. Compared to the previously reported structure with a single triangular air gap, this structure has stronger capacity of field confinement and microcavity bound with the same geometric parameters. So this structure is expected to be applied in the fields of on-chip interconnects, photonic integrated circuits, optical storage, and optical signal process.