• Photonics Insights
  • Vol. 1, Issue 1, R04 (2022)
Sanjib Ghosh1, Rui Su2、*, Jiaxin Zhao2, Antonio Fieramosca2, Jinqi Wu2, Tengfei Li1, Qing Zhang3、4, Feng Li5, Zhanghai Chen6, Timothy Liew2, Daniele Sanvitto7, and Qihua Xiong1、8、9、10、*
Author Affiliations
  • 1Beijing Academy of Quantum Information Sciences, Beijing, China
  • 2Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
  • 3School of Materials Science and Engineering, Peking University, Beijing, China
  • 4Research Center for Wide Gap Semiconductor, Peking University, Beijing, China
  • 5Key Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Laboratory of Information Photonic Technique, School of Electronic Science and Engineering, Faculty of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an, China
  • 6Department of Physics, College of Physical Science and Technology, Xiamen University, Xiamen, China
  • 7CNR NANOTEC, Campus Ecotekne, Lecce, Italy
  • 8State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, China
  • 9Frontier Science Center for Quantum Information, Beijing, China
  • 10Beijing Innovation Center for Future Chips, Tsinghua University, Beijing, China
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    DOI: 10.3788/PI.2022.R04 Cite this Article
    Sanjib Ghosh, Rui Su, Jiaxin Zhao, Antonio Fieramosca, Jinqi Wu, Tengfei Li, Qing Zhang, Feng Li, Zhanghai Chen, Timothy Liew, Daniele Sanvitto, Qihua Xiong. Microcavity exciton polaritons at room temperature[J]. Photonics Insights, 2022, 1(1): R04 Copy Citation Text show less


    The quest for realizing novel fundamental physical effects and practical applications in ambient conditions has led to tremendous interest in microcavity exciton polaritons working in the strong coupling regime at room temperature. In the past few decades, a wide range of novel semiconductor systems supporting robust exciton polaritons have emerged, which has led to the realization of various fascinating phenomena and practical applications. This paper aims to review recent theoretical and experimental developments of exciton polaritons operating at room temperature, and includes a comprehensive theoretical background, descriptions of intriguing phenomena observed in various physical systems, as well as accounts of optoelectronic applications. Specifically, an in-depth review of physical systems achieving room temperature exciton polaritons will be presented, including the early development of ZnO and GaN microcavities and other emerging systems such as organics, halide perovskite semiconductors, carbon nanotubes, and transition metal dichalcogenides. Finally, a perspective of outlooking future developments will be elaborated.

    1 Introduction

    Microcavity exciton polaritons are hybrid quasiparticles resulting from the quantum superposition of excitons and cavity photons inside semiconductor cavities[1]. As half-light, half-matter quasiparticles, they inherit all the advantages from their excitonic and photonic components, such as low effective mass, strong nonlinearity, fast propagation, as well as enhanced sensitivity to external stimuli, such as electric and magnetic fields. These advantages allow them to be an exceptional connecting bridge between condensed matter and photonic systems, which plays important roles in not only fundamental sciences but also novel optoelectronic and quantum applications[2]. In terms of fundamental physics, as interacting bosons with low effective masses, exciton polaritons are ideal candidates for investigating room temperature collective phenomena[3], such as non-equilibrium Bose–Einstein condensation[4], superfluidity[5,6], and quantum vortices[7]. With the advances of potential trapping in polariton systems[8], exciton polaritons can be trapped to serve as artificial atoms, opening a way to effectively emulate electron Hamiltonians. This unique property generally allows exciton polaritons to be a solid-state analog of cold atoms in optical lattices, which have been shown to play important roles in topology and proposed quantum simulators with room temperature operation. In addition, being intrinsically lossy due to the limited lifetimes of their components, exciton polaritons are also promising platforms for the investigation of rich non-Hermitian physics and related applications[9,10]. In the quest for practical applications, possessing spontaneous coherence in the condensation process, exciton polaritons allow realizing polariton lasers with thresholds orders of magnitude lower than that of conventional photonic lasers, because of the exemption of the population inversion process[11,12]. In addition, due to the strong nonlinearity from their excitonic components, exciton polaritons are excellent building blocks for developing all-optical ultrafast switches and transistors[1315], which lays the foundation for all-optical circuits[16] and chips. This strongly interacting nature also allows to induce quantum effects possibly at the level of single particles[17,18]. This promising regime brings exciton polaritons into the rapidly rising field of quantum simulation, computing, and information processing[19] with the possibility of room temperature operation.

    Sanjib Ghosh, Rui Su, Jiaxin Zhao, Antonio Fieramosca, Jinqi Wu, Tengfei Li, Qing Zhang, Feng Li, Zhanghai Chen, Timothy Liew, Daniele Sanvitto, Qihua Xiong. Microcavity exciton polaritons at room temperature[J]. Photonics Insights, 2022, 1(1): R04
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