题目：Room-Temperature Exciton Polariton Condensate and Lasing in Emergent Semiconductor Materials
   报告人：熊启华

时间：2019年11月11日上午9：30

地点：betway必威湖滨会议室

欢迎各位师生踊跃参加！

Abstract text:

 Microcavity exciton polaritons are part-light, part-matter strongly interacting Bosonic quasiparticles derived from strong light-matter coupling between excitons and microcavity photons, which have shown tremendous potential in quantum optics, ultrafast polaritonic switching and topological polaritonics. However, previous investigations are largely limited in pedagogic III-V GaAs quantum wells operating at only liquid helium temperatures constrained by the small exciton binding energy. Some organic materials show promise in exciton polaritonics at room temperature, nonetheless they usually suffer from large threshold density and weak nonlinearity due to the Frenkel exciton nature. In this talk, I will introduce our recent progress in realizing exciton polariton condensate and lasing in a few halide perovskite materials and atomically thin transition metal dichalcogenides. These effects are usually unambiguously evidenced by superlinear power dependence, macroscopic ground state occupation, blueshift of the ground state emission, and the build-up of long-range spatial coherence. Furthermore, we have shown the optical manipulating of such condensate by ultrafast propagation in 1D waveguides and 1D artificial polariton lattices. Interesting, modulated by deep periodic potentials, the polariton lattice exhibits a large forbidden bandgap opening up to 13.3 meV, which are at least 10 times larger than previous systems. Above a critical density, we observe exciton polariton condensation into py orbital states with long-range spatial coherence at room temperature. My final part of talk will discuss the first realization of ultralow threshold continuous-wave pumped polariton condensate in monolayer WS2 multiple quantum well cavity, with a Rabi splitting of ~37 meV and ~ 0.5 nW threshold. A long-range spatial coherence is identified across the entire condensate at room temperature. Our work advocates the room-temperature polaritonics with considerable promises in a wide range of applications, for instance electrically pumped polariton lasing and artificial polariton lattices for quantum simulator at room temperature.

References

1.       R. Su et al., “Observation of Exciton Polariton Condensation in a Perovskite Lattice at Room Temperature”, arXiv:1906.11566, accepted by Nature Physics, (2018)

2.       R. Su et al., “Room temperature one-dimensional polariton condensate propagation in lead halide perovskites”, Science Advances, DOI: 10.1126/sciadv.aau0244 (2018)

3.       R. Su et al., “Room temperature polariton lasing in all-inorganic perovskite”, Nano Lett. 17, 3982–3988 (2017)

4.       Q. Zhang, et al., “High quality whispering-gallery-mode lasing from cesium lead halide perovskite nanoplatelets”, Adv. Funct. Mater. 26, 6238-6245 (2016)

5.       Q. Zhang, et al., “Room-temperature near-infrared high-Q perovskite whispering-gallery planar nanolasers”, Nano Lett. 14, 5995-6001 (2014)

Biography:

熊启华是南洋理工大学数理科学学院教授。美国物理学会会士。1997年本科毕业于betway必威物理系，2000年从上海应用物理研究所获得硕士学位，2006年于宾夕法尼亚州立大学获得博士学位，师从Peter C. Eklund教授。2006-2009年在哈佛大学Charles Lieber研究组从事博士后研究。2009年初获得新加坡国立研究基金研究员项目资助并于当年6月加入南洋理工大学，任南洋助理教授。2014年获得终身教职，2016年升正教授。2014-2019年担任数理科学学院副院长主管科研和研究生教育及教职事务。熊启华教授的主要研究领域是半导体光学以及低维半导体纳米材料基于光子-声子-电子耦合作用的物理机制和量子调控。在《自然》及子刊, 《科学进展》，《纳米快报》，《先进材料》等一系列国际知名杂志上发表了220多篇文章，并被世界知名杂志及大众媒体所报道，总引用次数超过11000次，H-因子63。其出色的研究获得了一些奖励和认可，比如新加坡物理学会纳米科技奖（2015），新加坡国立研究基金NRF Investigatorship奖（2014），和南洋理工大学南洋研究卓越奖（2014）等。 2018年起，担任美国光学学会旗舰杂志《Optics Express》副主编, Wiley信息材料领域新创刊杂志《InfoMat》的副主编和《半导体学报》副主编。