报告题目：Optical nonlinearity enhancement of excitons strongly coupled to a Fabry-Perot cavity
报 告 人：王魁东 博士， 斯特拉斯堡大学（法国）
报告时间：2021年11月6日，15：00
报告地点：腾讯会议（ID 807 845 573）
报告邀请人：王绍军
报告摘要：
Strong coupling between excitons of materials and optical modes paves the way for understanding the light-matter interactions. [1]With the existence of these hybrid light-matter states, many properties of the material, including the conductivity of the organic semiconductor [2], the dynamics of the molecule [3] and the energy transfer rate between molecules [4], can be modified remarkably. Besides, recent studies also connected the hybrid light-matter states of organic materials with their nonlinear optical responses. For instance, second harmonic generation [5] can be enhanced remarkably under strong coupling condition. However, the measurements in those work are only focused on specific nonlinear optical phenomena, which limits their generality in nonlinear optics. In addition, the synthesis of those molecules are quite complicated, which also preclude their practical applications.
In our work, we strongly coupled the excitons of J-aggregate cyanine molecules (TDBC) to an optical mode in a Fabry-Perot cavity, and measured the nonlinear refractive index (n2) and nonlinear absorption coefficient (β) of the coupled system via Z-scan technique. Under the polaritonic states, these coefficients can be enhanced more than 2 orders of magnitude compared with that of the uncoupled molecule. In addition, the coupled system shows ~120-fs dynamics, which shows promising applications in ultrafast optical switching. This work makes it possible to study the effect of strong coupling on various third-order nonlinear optical phenomena [6].
References:
[1] J. Francisco, et al., Science, 373, abd0336 (2021);
[2]E. Orgiu, et al., Nat. Mater.14, 1123 (2015);
[3] T. Schwartz, et al., ChemPhysChem14, 125 (2013);
[4] X. Zhong, et al., Angew. Chem. Int. Ed.55, 6202 (2016);
[5] T. Chervy, et al., Nano Lett.16, 7352 (2016);
[6] K. Wang, et. al., Nat. Commun.12, 1486 (2021).
报告人简介：
Dr. Kuidong WANG completed his doctorate in optics with the combination of ultrafast laser spectroscopy and plasmonics at Key Laboratory for Laser Plasmas, Ministry of Education, Shanghai Jiao Tong University in 2018. After that, he joined Prof. Thomas Ebbesen’s group as a postdoc researcher in University of Strasbourg, France. His research work focuses on exploring the static and dynamic optical nonlinearities of the light-matter hybrid systems in the case of strong coupling and weak coupling conditions. In addition, he is also studying the enhancement of the ultrafast optical nonlinearity on metallic nanostructures with plasmonic effects.