报告题目：Optical Multi-dimensional Coherent Spectroscopy: from Atoms to Semiconductor Nanomaterials

报告人：李鹤槟（Hebin Li）,博士，美国佛罗里达国际大学(FIU)助理教授（Assistant Professor）。  

时间：2019年3月12日  下午2：00

地点：大学城校区理六栋220

摘要：The concept of multi-dimensional coherent spectroscopy originated in nuclear magnetic resonance (NMR) where it revolutionized NMR studies of molecular structure and dynamics. In the past decades, the same concept has been implemented in the optical region with femtosecond lasers. In the experiment, the nonlinear response of a sample to multiple laser pulses is measured as a function of time delays. A multi-dimensional spectrum is constructed by taking a multi-dimensional Fourier transform of the signal with respect to multiple time delays. Compared to conventional 1D spectroscopic techniques, Optical Multi-dimensional Coherent Spectroscopy (MDCS) excels in studying coupling and dynamics in complex quantum systems. For example, optical MDCS has been a powerful tool for studying many-body interactions in atoms, energy transfer in photosynthesis, and many-body physics in semiconductor nanomaterials.

In this presentation, I will first introduce the idea of optical MDCS and its experimental implementations in our lab. I will then talk about its applications in studying many-body physics in atoms and semiconductor including quantum wells and 2D materials. In atomic vapors, double-quantum 2DCS provides an extremely sensitive and background-free detection to dipole-dipole interactions. The resulting 2D spectra reveal effects of dipole-dipole interactions at a mean interatomic distance of micrometers, confirming the long-range nature of dipole-dipole interaction. The technique can also be extended to multi-quantum coherent spectroscopy to provide direct evidence of multiple-atom correlated states (Dicke states) up to 7 atoms. Besides atomic vapors, optical multi-dimensional coherent spectroscopy is also a powerful tool for studying many-body dynamics and coupling in semiconductor nanomaterials. I will present several applications in semiconductor quantum wells and 2D materials, where unique information about the carrier dynamics can be obtained from 2D spectra.

报告人简介：

李鹤槟（Hebin Li）,博士，美国佛罗里达国际大学(FIU)助理教授（Assistant Professor）。

李鹤槟博士于2001年毕业于武汉大学，获物理学学士学位。2010年获美国Texas A&M University物理学博士学位，师从国际著名量子物理学家Marlan Scully 教授。2010-2013年于美国JILA实验室Steven Cundiff 教授研究组从事博士后研究；2013年加入FIU物理系。李鹤槟博士主要从事激光场与原子相互作用的动力学过程及相干调控、激光场与半导体纳米结构（量子井、原子级二维体系等）相互作用的动力学过程及相干调控、多维超快Fourier变换光谱技术及应用等方面的研究，先后在Nature、Nature comunication，Physics review Letter、Physics review B、Optical letter等刊物发表学术论文40余篇，在光学相关领域多次受邀做学术报告，是PRL、PRA、PRB、Optics Letter、JOSAB、JPC、Applied Optics等刊物以及美国国家科学基金（NSF）、美国化学协会石油研究基金（ACS PRF）等项目评审人。