Wang Yafeng, Liao Liming, Hu Tao, Luo Song, Wu Lin, Wang Jun, Zhang Zhe, Xie Wei, Sun Liaoxin, Kavokin A V, Shen Xuechu, Chen Zhanghai
State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing Jiangsu 210093, China.
University of Southampton, Highfield, Southampton SO249QH, United Kingdom.
Phys Rev Lett. 2017 Feb 10;118(6):063602. doi: 10.1103/PhysRevLett.118.063602. Epub 2017 Feb 8.
Angle-resolved second harmonic generation (SHG) spectra of ZnO microwires show characteristic Fano resonances in the spectral vicinity of exciton-polariton modes. We observe a resonant peak followed by a strong dip in SHG originating from the constructive and destructive interference of the nonresonant SHG and the resonant contribution of the polariton mode. It is demonstrated that the Fano line shape, and thus the Fano asymmetry parameter q, can be tuned by the phase shift of the two channels. We develop a model to calculate the phase-dependent q as a function of the radial angle in the microwire and achieve a good agreement with the experimental results. The deduced phase-to-q relation unveils the crucial information about the dynamics of the system and offers a tool for control on the line shape of the SHG spectra in the vicinity of exciton-polariton modes.
ZnO微线的角分辨二次谐波产生(SHG)光谱在激子极化激元模式的光谱附近显示出特征性的Fano共振。我们观察到,在SHG中,一个共振峰之后紧接着一个强烈的凹陷,这源于非共振SHG的相长和相消干涉以及极化激元模式的共振贡献。结果表明,Fano线形,进而Fano不对称参数q,可以通过两个通道的相移来调节。我们建立了一个模型来计算作为微线中径向角函数的与相位相关的q,并与实验结果取得了良好的一致性。推导得到的相位与q的关系揭示了关于系统动力学的关键信息,并为控制激子极化激元模式附近SHG光谱的线形提供了一种工具。