深亚波长约束的表面等离子体纳米激光器研究

Study of plasmonic nanolaser based on the deep subwavelength scale

本文提出了一种新颖的基于半导体纳米线/空气间隙/金属薄膜复合结构的表面等离子体纳米激光器,并给出了理论研究和仿真分析.这种结构通过金属界面的表面等离子体模式与高增益介质纳米线波导模式耦合,从而使场增强效应得到显著提高.同时通过数值仿真研究,得到该混合波导结构的模式特性和增益阈值随空气槽宽度、纳米线半径的变化规律,表明它可以实现对输出光场的深亚波长约束,同时保持低损耗传输和高场强限制能力.通过最优化选择,最终得到纳米等离子体激光器的最优结构尺寸.

We have proposed a novel surface plasmonic nanolaser based on a nanowire/air gap/metal thin film hybrid structure to carry out theoretical research and simulation analysis. Opening an air groove in the MgF2 insulating layer, then making a nanowire embedded on the top of the air slot but maintaining a gap between the nanowire and the metal layer, thereby we produce a coupled hybrid plasmonic waveguide and a significant field enhancement effect. This structure enables the realization of an air gap. By simulating the modal properties and the lasing threshold of the hybrid plasmonic mode under different geometric parameters, the capacity of subwavelength scale with low propagation loss and high field confinement is demonstrated. Finally we achieve the nanolaser＇s optimal structure size. Compared with the general diffraction limit laser, this structure can reduce the physical size of the device and the physical mode. The proposed nanolaser could be easily integrated with various nanophotonic devices, and it may become an appealing candidate for future active plasmonic systems.