激子极化激元光子学研究进展

研究光与物质相互作用是腔量子电动力学的一个重要方向.早在20世纪50年代,黄昆先生就提出了固体环境中的光子与晶格连续作用的时间演化图像,并指出光子-声子时间上连续不断的相互转化会在物质中形成声子极化激元波,从理论上计算了声子极化激元波的色散关系.Hopfield把这种图像推广到半导体环境中的光子-激子作用上.随后人们在微腔中实现了单原子、单量子点激子的真空拉比振荡.随着半导体微腔生长和微纳加工工艺的提高,激子极化激元的凝聚、超流、涡旋等宏观量子态被实验证明.通过控制微腔结构和光场调控的手段,人们进一步实现了对宏观量子态的相干调控.有机半导体、钙钛矿、二维半导体等新材料体系展现了极大的激子束缚能,有望实现室温量子器件的制备.微腔激子极化激元的研究进入了黄金时代.本文首先从激子极化激元的基本图像入手,详细介绍激子极化激元的概念、色散关系以及常见的激子极化激元体系.其次,总结了研究微腔激子极化激元的材料体系和实验方法,详细介绍了平板微腔和微纳材料自构型微腔的工作原理和具体实例,以及共焦显微荧光光谱和角分辨荧光光谱.第三,对激子极化激元的量子调控进行了总结.详细介绍了激子极化激元的重要宏观量子态以及通过微纳加工和光场调控的方式对宏观量子态的操控.具体分析了两个量子态操控的实例,包括氧化锌超晶格中多重量子态的制备以及凝聚体的参量散射过程.第四,对新型材料中激子极化激元的研究进行了总结,包括二维半导体、有机半导体和钙钛矿.最后,对本文进行总结,并且从理论、实验的角度分别预测了该领域的发展趋势.

Progress on exciton polariton photonics

Control of light-matter interactions is crucial for the development of cavity quantum electrodynamics.In the 1950s,Huang developed a model to describe photon-phonon interactions in solid-state systems.In this model,when a phonon and a photon exchange energy continuously and coherently,the system can reach a strong coupling regime and a new quasiparticle called"polariton"can be formed.Huang’s theory also describes the dispersion of phonon polaritons.This theory has been applied to semiconductors by Hopfield,wherein an exciton and a photon can couple with each other,reaching new eigenmodes called"exciton-polaritons".Subsequently,vacuum Rabi splitting has been observed in a microcavity that is strongly coupled to a single atom or a single quantum dot.Microcavities of a higher quality factor display macroscopic quantum phenomena such as polariton condensation,superfluidity,and vortices.By applying nanofabrication techniques on the cavity or controlling the beam profile of a pumping laser,various potentials can be induced in polariton systems that enable the manipulation of macroscopic quantum states.Excitons exhibit much larger binding energies and oscillator strengths in emerging materials such as organic semiconductors,perovskites,and twodimensional semiconductors,providing a new platform to extend polariton physics to room-temperature devices.Microcavity exciton-polaritons are the leading candidate systems for studying quantum optics and condensed matter physics.This review first introduces microcavity exciton-polaritons,including the formation of exciton-polaritons,energy-momentum dispersion of exciton-polaritons,and polariton systems classified by the gain medium.We then introduce several systems to achieve strong coupling and a microspectroscopic technique to investigate excitonpolaritons.The third section provides an analysis of the macroscopic quantum states of exciton-polaritons and describes how to manipulate the quantum state using nanofabrication and optical pumping techniques.The fourth section summarizes several new materials that have been used to study exciton-polaritons at room temperature.The last section summarizes this review,and provides perspectives in both theories and experiments.