低维受限胶体量子点/氧化锌管状复合光学微腔耦合效应及光谱调制效应研究

Based on the coupling effects of radiation source and microcavity, the design, preparation, physical properties and optical amplification effects of low dimensional, easy modulaiton and multifuctional microcavities are attracting tremendous attentions in the field of semiconductor microcavity, which is essential for the development and application of novel optolectronic divices in the future. In this project, zinc oxide microcavity with the unique hollow tubular structure is used as testbed. II-VI group quantum dots with tunable emission properties are combined with the microcavity by micro-nanofilling technique. We investigate the coupling effect, kinetic spectroscopic properties and optical amplification by using the multi-dimensional resolved spectroscopic technique and the time-correlated single photon counting technique. The optical properties of composite microcavity influenced by quantum dot size, type, fill factor and the quality factor of the microcavity will be comprehensively studied. By tuning the temperature, we can control precisely the energy detuning between excitons of the quantum dots and the cavity modes, and observe the crossing behavior at the energy resonance region. In addition, tunable lasing in a wide spectral range from the quantum dots in the microcavity will be studied. Combined with the theoretical analysis, we will clarify the physical nature of the novel phenornena induced by the composite microcavity, and explore the effective method to control the optical field in a wide range. Through this project, we expect that outstanding achievements can be obtained in the technological and physical investigation of the coupling effects in the colloidal quantum dots/zinc oxide composite microcavities.

基于辐射光源与微腔之间的耦合效应，进行宽波谱、易调谐、多功能、低维受限微腔系统的设计、制备、物理特性及光放大效应研究是当前半导体光学微腔领域的热点，对未来新型微腔基光电子器件的开发应用具有非常重要的意义。本项目以具有独特空心管状几何结构的氧化锌微腔为载体，通过微纳填充复合技术，将具有尺寸可调谐发光性能的II-VI族核壳结构胶体量子点与微腔有效复合，利用多维分辨显微荧光探测技术和时间关联单光子计数技术，研究量子点/氧化锌管状复合微腔耦合效应、光谱动力学特性及光放大效应，解析量子点尺寸、种类、填充复合因子及微腔品质对光谱调制的影响，实验上实现温度依赖的腔模与激子能量从非共振到共振的转变以及微腔调制的量子点多波长、可调谐激射，并结合理论分析，深入理解复合微腔所诱发的各种新奇现象的物理本质，探寻针对宽波谱、多波长光场低维有效调控手段，力争在胶体量子点/微腔耦合相关的技术应用和物理探索方面有所突破。

基于外加辐射光源和微腔之间的耦合效应，对自发辐射进行控制，是当前半导体光学微腔领域的研究热点，对新型光电器件如激光器、单光子源以及光电振荡器等具有非常重要的意义。本项目采用传统的碳热还原技术，制备出表面光滑，形状规则，具有规则正六边形截面的单晶氧化锌微米棒状回音壁微腔，并在实验上给出该结构室温下微腔调制的光谱物理图像；另外我们还采用水辅助碳热还原技术，获得表面光滑，形状规则的六边形截面氧化锌微米管状微腔，并且实现了不同壁厚氧化锌微米管晶体的可控生长，提出其生长机理；另外我们此案用一锅法合成了高品质的II-VI族核壳胶体量子点，量子点分散性好、晶体质量高且发光效率高、光谱半峰宽窄。我们采用多次浸润的方法将油相量子点均匀的复合再氧化锌棒状和管状微腔，复合微腔体系光谱中氧化锌和量子点的发光都收到微腔的调制，发现管状微腔对量子点的耦合效果更好。通过计算，我们确定了基于全反射模型的回音壁模式，并且利用有限元（FEM）模拟进行进一步确定。此外，对胶体量子点相关的谐振特性进行了细节的研究。同时，我们还发现了在量子点与氧化锌微腔之间的荧光共振能量转移现象。本项目基于量子点/微腔复合体系，实现了宽波段、可调谐光场低微调控，对于量子点/微腔耦合相关的技术应用和物理探索方面具有重要的意义。