金纳米凸起形貌和尺寸对自发辐射增强的影响

Effect of Protrusion Morphology and Size of Gold Nano on Spontaneous Emission Enhancement

表面等离激元具有局域场增强效应,在诸多领域具有广泛的应用,包括自发辐射、新型集成光电子器件、高灵敏生物检测和新型光源等.基于经典局域响应近似模型(LRA)、非局域流体动力学模型(HDM)、广义非局域光学响应模型(GNOR)和量子流体动力学模型(QHT),研究截面金球中不同尺寸的圆锥和圆台形凸起对自发辐射增强特性的影响.结果表明:对自发辐射增强谱,相比于LRA,非局域HDM和GNOR峰位均蓝移,峰值急剧降低,而QHT峰位红移,峰值未改变;随圆锥和圆台增高,自发辐射增强谱的峰值增大;相比于锥形凸起结构,圆台形凸起结构中的自发辐射增强峰值较大;随台面半径减小,QHT中的自发辐射增强谱峰值增大,而HDM和GNOR中的峰值减小.

The local field enhancement effect of surface plasmons has been widely used in many fields,including spontaneous emission enhancement,novel integrated optoelectronic devices,highly sensitive biological detection,and novel light sources.The different optical response models are adopted to investigate the spontaneous emission enhancement around a gold atomistic protrusion with a cone or a truncated cone shape of different sizes,including the classical local response approximation model(LRA),the nonlocal hydrodynamic model(HDM),the generalized nonlocal optical response model(GNOR)and the quantum hydrodynamic model(QHT).Compared with LRA,the spontaneous emission enhancement blueshifts and decreases rapidly under the HDM model and GNOR model.However,the spontaneous emission enhancement redshifts and has little effect on the peak under the QHT model.The higher the protrusion is,the larger enhancement can be observed.The spontaneous emission enhancement of a truncated cone shape structure is stronger than cone shape structure.In QHT,the spontaneous emission enhancement increases with the decreasing of the truncated cone radius.But the peak decreases under the HDM model and GNOR model.