表面等离激元与半导体微腔的耦合及其对激子极化激元单光子与双光子自发辐射的调控研究

The coupling between the surface plasmon polariton and the semiconductor microcavity will change the cavity modes and control the single-photon and the two-photon spontaneous emission of the exciton polariton.This project will investigate the coupling between the exciton polariton and the surface plasmon polariton in the microcavity, its effect on the microcavity modes, and the control to the spontaneous emission of the exciton polariton. The project will investigate the coupling of the plasmon polariton in the microstructure of semiconductor microcavity/dielectri layer/metal, analyze the eigen modes of the exciton polariton with different coupling of the plasmon polariton. The focus of this research is the effect of the coupling intensity with the change of the dielectric layer thickness.The project will investigate the coupling effect of the plasmon polariton on the microcavity modes in the whole visible waveband and analyze the dispersion of the coupling. The project will determine the microcavity modes with different coupling of the plasmon polariton in the whole visible waveband. This project will also investigate the quality factor of the microcavity with the coupling of the plasmon polariton from the violet to visible waveband.In the above investigations, theoretical researches with the finite element method will also be made. With the software COMSOL for the finite element mothod, the coupling between the plasmon polariton and the microcavity will be investigated in details. The eigen mode of the exciton polariton, the coupling at different wavelength and the quality factor of the microcavity will be investigated with the finite element analysis, which will deepen the understanding of the coupling between the plasmon polariton and the semiconductor microcavity. Another main task of the project is the investigation into the two-photon spontaneous emission of the exciton polariton with the coupling of the plasmon polariton.The project will investigate the modes，the polarizations and the efficiency of the two-photon emission of the exciton polariton and determine the relation between the two-photon emission efficiency and the coupling of the plasmon polariton. The achievement of the project may be used in the area of the sub-wavelength optoelectronics.

表面等离激元与半导体微腔的耦合将改变微腔的模式特性，并调控半导体微腔中激子极化激元的单光子与双光子自发辐射特性。本项目将研究微腔中激子极化激元与表面等离激元的耦合规律，研究该耦合对微腔模式的影响，分析该耦合对激子极化激元的自发辐射的调控规律。项目同时将研究表面等离激元在整个可见光波段内对微腔模式的影响，分析耦合的色散规律。项目还将分析从紫外到整个可见波段范围内表面等离激元耦合对半导体微腔品质因子的影响。项目的另一研究重点是研究表面等离激元耦合对微腔中激子极化激元双光子自发辐射的调控规律及其模式分布，特别是双光子辐射的偏振与单光子辐射偏振的关系。分析研究耦合强度对双光子辐射效率的影响，确定双光子辐射效率与等离激元耦合的关系。本项目的研究成果在亚波长光电子领域有广泛的应用前景，将丰富人们对等离激元与半导体微腔耦合规律的认识。

本项目立项以来，对金属表面等离激元与半导体微腔的耦合机制及其对激子极化激元自发辐射特性调控等相关问题进行了详细的研究，并取得了一批有意义的成果。研究发现，无论在带边辐射区还是可见光区金属表面等离激元与氧化锌半导体微腔都有强烈的耦合，该耦合可以由有效折射率进行定量描述，由此实现了对表面等离激元、微腔与激子极化激元耦合的定量描述。结果显示，耦合导致的有效折射率显著小于材料的固有折射率。项目组在微腔中除了观察到常规的Fabry-Perot模式，还观察到由Fabry-Perot模式和回音壁模式同时存在时的模式包络。项目组详细研究了金属纳米球与半导体纳米圆柱型微腔耦合时的模式变化，该耦合使圆柱型微腔中二度简并的基模不再简并，并分成耦合模式与非耦合模式两个独立的模式，其中的耦合模式的性质将发生根本的变化，在适当条件下可以使该模式的Purcell因子显著变化。项目组还研究了金属等离激元与半导体量子点的耦合规律，在表面等离激元与半导体量子点的耦合将增强双激子效应，同时在CdSe/ZnS量子点中，可以由表面等离激元增强Raman效应观察到核壳结构量子点界面处的CdS模，在与银纳米晶耦合的量子点中，可以观察到快慢两个荧光复合过程，其中快过程对应于银纳米晶与量子点之间的快速载流子转移过程。