讲座信息：“An Introduction to Exciton-Polariton Lasing”
主讲嘉宾： Prof. Ji Wei (季伟 教授)
Since the invention of lasers in 1960, lasers have made tremendous impacts onto modern technologies in both fundamental scientific research and massive industries, such as communications. One of the challenges for making lasers is how to make them more efficient and more compact. Recently, there has been increasing attention on an exciton-polariton mechanism, which should make micro-lasers with the lasing threshold being considerably lower, as compared to conventional lasers based on the creation of population inversion.
In this talk, I will start to give an introduction on the fundamental physics of exciton-polariton. Then, I will report our recent research towards to exciton-polariton lasing. In particular, I will present our observation of multimode exciton−polaritons in single-crystalline microplates of a two-dimensional (2D) layered metal−organic framework (MOF), which can be synthesized through a facile solvothermal approach, thereby eliminating all fabrication complexities usually involved in the construction of polariton cavities. With a combination of experiments and theoretical modeling, we have found that the exciton−polaritons are formed at room temperature as a result of a strong coupling between Fabry−Perot cavity modes formed inherently by two parallel surfaces of a microplate and Frenkel excitons provided by the 2D layers of dye molecular linkers in the MOF. Flexibility in rational selection of dye linkers for synthesizing such MOFs renders a large-scale, low-cost production of solid-state, micro-exciton−polaritonic devices operating in the visible and near-infrared range. Our work introduces MOFs as a new class of potential materials to explore polariton-related lasing and other quantum phenomena in a cost-effective manner.
Wei Ji received his PhD degree in Physics at Heriot-Watt University, Edinburgh, Scotland in 1986. After the experience of three-year post-doctor at the same university, he moved to National University of Singapore as Lecturer, Associate Professor, and Full Professor. He was the Vice Dean of Science Faculty, National University of Singapore for seven years. He was an Associate Editor of Optical Materials Express. His current research interests include nonlinear optical materials, especially low-dimensional semiconductors and organics, and their technological applications for optical switching, optical limiting, lasing, and optical detection.