改进型混合表面等离子体微腔激光器的研究

设计了一种拥有增益介质脊和空气间隙的改进型混合表面等离子体微腔激光器,并在微腔的两端面镀一层50 nm厚的银反射镜,有效地提高了纳米激光器的性能.基于COMSOL Multiphysics软件分别构建二维截面和三维立体模型,在1550 nm的工作波长下对该改进型结构的传输性能以及微腔性能进行分析.结果表明:该激光器具有显著的亚波长限制能力和很大的传输距离,最长距离可以达到1.29 mm.测试该激光器的微腔性能时,通过调整结构参数获得了高质量因子、低增益阈值以及深亚波长下的超小有效模式体积0.001092μm~3和超高的Purcell因子8.29×10~5.与先前结构对比,在结构参数统一时,所设计的结构具有更低的激光激射阈值和更强的微腔局域能力.所设计的改进型混合表面等离子体微腔激光器可以作为各种光子器件的基本构建模块,并可应用于传感、纳米聚焦和纳米激光等领域.

Improved hybrid plasmonic microcavity laser

In this paper, an improved hybrid surface plasmon nanolaser with a gain medium ridge and a layer of air gap is proposed. In order to achieve low propagation loss and sub-wavelength field confinement, a triangular air gap and a 50 nm microcavity end face silver mirror are adopted in this structure, and the combination of this particular triangular structure and silver mirror effectively improves the performance of nano-laser. In this paper, we numerically simulate the waveguide by using the finite-element method. The COMSOL multiphysics software is a superior numerical simulation software to simulate the real physical phenomena based on the finite element method. On the basic of the COMSOL multiphysics software, a two-dimensional cross-section model and a three-dimensional model are built, the transmission performance and microcavity performance of the improved structure are analyzed in detail at a working wavelength of 1550 nm. Some quantities including the electric field distribution, transmission length, normalized mode field area, average energy density, foundation modal volume, quality factor of the structure, threshold gain, quality factor, effective modal volume, and Purcell factor are considered here which are dependent on the dielectric constant and geometrical parameters. The results indicate that on a two-dimensional scale, the contradiction between transmission loss and transmission distance can be effectively solved by the guidance of Fom value, and the IHPM laser structure with optimal transmission characteristics is obtained under the guidance of quality factor and foundation modal volume. A deep sub-wavelength constraint on light is achieved:the propagation length of the electromagnetic mode reaches a millimeter level and the longest distance can reach 1.29 mm. When testing the microcavity performance of the laser separately on a two-dimensional scale and three-dimensional scale, the high quality factor, low gain threshold, ultra-small effective mode volume of 0.001092 μm³ and ultra-high Purcell factor of 8.29×10⁵ are obtained by adjusting the structural parameters and plating a 50 nm-thick silver layer on the end face of the laser microcavity. Compared with the previous structure without air gaps, the designed structure has a low laser lasing threshold and strong micro-cavity local capability when these two structural parameters are unified. The designed hybrid surface plasmon nanolaser may serve as a fundamental building block for various functional photonic components and can have applications such as in sensing, nanofocusing, and nanolasing.