Ye Ziyu, Chen Fei, Zhou Hang, Luo Song, Sun Fenghao, Sun Zheng, Zheng Yuanlin, Chen Xianfeng, Xu Huailiang, Chen Zhanghai, Li Hui, Wu Jian
State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, People's Republic of China.
Department of Physics, College of Physical Science and Technology, Xiamen University, Xiamen 361005, People's Republic of China.
J Phys Condens Matter. 2022 Mar 29;34(22). doi: 10.1088/1361-648X/ac5e04.
Based on ZnO microcavities with high quality factors, where the gain medium exhibits confinement of wave packets due to the intrinsically formed whispering gallery microcavity, strong coupling between excitons and cavity photons can be obtained at room temperature resulting in hybrid quasiparticles, e.g. exciton polaritons. In this work, polariton condensation is induced under the non-resonant excitation by linearly polarized femtosecond laser pulses with different polarization directions. The dynamical angle-resolved-space spectra of the photoluminescence emission of polariton condensates are measured with sub-picosecond resolution by the self-developed femtosecond angle-resolved spectroscopic imaging technique. Our results show that the ultrafast dynamics of polariton condensation is sensitive to the polarization direction of the excitation pulses which can be explained qualitatively by the combined effect of selective excitation of distinct exciton modes in the sample and the effective coupling strength of the excitation pulses in the ZnO microcavity for various polarization directions. This work strengthened the understanding of the condensation process for cavity exciton polaritons at room temperature.
基于具有高品质因数的ZnO微腔，其中增益介质由于固有形成的回音壁微腔而表现出波包的限制，在室温下可以获得激子与腔光子之间的强耦合，从而产生混合准粒子，例如激子极化激元。在这项工作中，通过具有不同偏振方向的线偏振飞秒激光脉冲在非共振激发下诱导极化激元凝聚。利用自行研制的飞秒角分辨光谱成像技术，以亚皮秒分辨率测量了极化激元凝聚体光致发光发射的动态角分辨空间光谱。我们的结果表明，极化激元凝聚的超快动力学对激发脉冲的偏振方向敏感，这可以通过样品中不同激子模式的选择性激发以及ZnO微腔中激发脉冲在各种偏振方向上的有效耦合强度的综合效应来定性解释。这项工作加深了对室温下腔激子极化激元凝聚过程的理解。
