表面等离激元纳米球中量子和非局域效应对自发辐射动力学的影响

Effect of Quantum and Nonlocal Effects in Surface Plasmon Nanospheres on Decay Dynamics

基于局域响应近似模型(LRA)、非局域流体动力学模型(HDM)、广义的非局域光响应模型(GNOR)和量子流体动力学理论(QHT),利用格林函数预解算子方法,研究钠金属球附近原子的自发辐射动力学特性.对于自发辐射增强谱,在LRA、非局域HDM和GNOR中,量子压力导致峰位蓝移,峰值急剧降小,而在QHT中,电子溢出导致峰位红移,峰值急剧增大.系统研究不同跃迁频率和偶极矩对自发辐射动力学的影响,当原子的跃迁频率与QHT下自发辐射增强谱的峰值相等时,不同模型下呈现出指数衰减和Rabi振荡的特征;而当原子跃迁频率远小于共振频率时,对较小的跃迁偶极矩,动力学均呈现出指数衰减.为获得表面等离激元-原子束缚态,QHT模型下的临界偶极矩最小,而HDM和GNOR模型所需的临界偶极矩最大.

Based on the classical local response approximation(LRA),the non-local hydrodynamics model,the generalized nonlocal optical response model(GNOR)and the quantum hydrodynamics theory(QHT),the resolvent operator technique is used to investigate the decay dynamics of atom located around a sodium nanosphere.For the spontaneous emission,quantum pressure in LRA,non-local HDM and GNOR leads to a blueshift of the peak position and a sharp decrease of the peak,while in QHT,the electron spill-out leads to a red shift of the peak position and a sharp increase of the peak.The effects of different transition frequencies and dipole moments on the decay dynamics are systematically studied.When the transition frequency of the atoms equals the peak of the QHT spontaneous emission,different models show the characteristics of exponential decay and Rabi oscillations.When the atomic transition frequency is much lower than the resonance frequency,for a little smaller dipole moment,the dynamics show exponential decay.To obtain the a surface plasmonicatom bound state,the critical dipole moment of the QHT model is the smallest,while the critical dipole moment of the HDM and GNOR models is the largest.