基于碱金属等离激元的低阈值纳米激光器  

Low Threshold Nanolasers Based on Alkali Metal Plasmons

作　　者：滕达 胡蓉蓉 程铭雅 郝勇志 张哲 陈燕燕 聂红阳 王天顺 申梓刚 Teng Da;Hu Rongrong;Cheng Mingya;Hao Yongzhi;Zhang Zhe;Chen Yanyan;Nie Hongyang;Wang Tianshun;Shen Zigang(College of Physics and Electronic Engineering,Zhengzhou Normal University,Zhengzhou 450044,Henan,China)

机构地区：[1]郑州师范学院物理与电子工程学院,河南郑州450044

出　　处：《中国激光》2025年第2期288-296,共9页Chinese Journal of Lasers

基　　金：河南省高等教育教学改革研究与实践项目(2024SJGLX0524);河南省自然科学基金(242300420667);河南省高等学校重点科研项目(24B140014);河南省高等学校大学生创新创业训练计划(202412949007);郑州师范学院大学生创新创业训练计划目(DCZ2023019);郑州师范学院大学生科研创新基金(2024002);郑州师范学院本科教学改革研究项目(JXGGYB-232234)。

摘　　要：设计了一种由三角形Na纳米线和Si纳米线组成的混合等离激元波导,采用有限元方法研究了该波导模式特性及其在等离激元纳米激光器中的应用。重点研究了有效模式系数、传播长度、归一化模场面积、品质因数、限制因子、增益阈值和Purcell因子等性能指标。所设计的波导具有极强的场约束能力和高品质因数,归一化模场面积在~10^(-5)量级且品质因数大于3000。得益于Na等离激元的低损耗特性及尖端结构对光场的优异约束特性,增益阈值低至0.118μm^(-1),Purcell因子大于220。与类似结构相比,所提出结构的阈值显著降低,Purcell因子大幅提升。此外,研究发现,器件性能对制造偏差有着很好的容忍度。研究结果对于其他类型的Na基低损耗等离激元波导的发展具有一定的指导和借鉴意义,推动了碱金属在亚波长光子器件中的应用。Objective Plasmonic waveguides can compress light into regions significantly smaller than the diffraction limit and have emerged as a promising candidate for achieving nanoscale field confinement.To date,various types of plasmonic waveguides have been proposed and widely used for the development of integrated optical devices,including nanolasers,modulators,splitters,and resonators.However,the strong optical-field-confinement ability of noble metal-based plasmonic devices is typically accompanied by their inherent Ohmic loss,which severely hinders their applications at the nanoscale.Recent studies show that alkali metal sodium presents lower loss than metal silver,and that the free-electron relaxation time of sodium is approximately double that of silver.The utilization of alkali metals can potentially decrease the optical loss of plasmons significantly,thus facilitating investigations into light-matter interactions at the nanoscale.In this study,we propose a hybrid surface plasmon waveguide structure comprising triangular-shaped sodium and silicon nanowires,which effectively confines light fields in the low-refractive-index spacer and at long transmission distances(>40μm).In particular,owing to its low modal loss and excellent optical-field confinement ability,the proposed hybrid plasmon waveguide demonstrates an extremely low gain threshold and a large Purcell factor.Additionally,the effect of lateral-position deviation on modal and lasing properties is investigated,and the results show robustness against position deviations.Hence,the proposed structure is feasible as building blocks for subwavelength photonic devices,such as nanolasers and modulators.Methods The proposed hybrid plasmonic waveguide structure(Fig.1)comprises a triangular-shaped sodium nanowire separated from a triangular-shaped silicon nanowire by a gap distance(g).The waveguide and lasing performances were investigated using the finite-element method(FEM)and characterized using the effective mode index[n_(eff)=Re(N_(eff))],propagation length(L_

关 键 词：光学器件 等离激元波导 纳米激光器 增益阈值 

分 类 号：O436[机械工程—光学工程]