报告题目： Ultrafast Laser Spectroscopy of Two-Dimensional Materials

报告人： 赵辉  (University of Kansas, U.S.)

报告时间：2019年6月14日 上午10:00

报告地点：物理学院新楼五楼多功能厅

报告摘要：

In this seminar, recent studied on optical and electronic properties of two-dimensional materials by ultrafast laser spectroscopy will be presented. Two-dimensional materials, such as graphene, MoS₂, WS₂, and black phosphorus are promising materials for future electronic and optoelectronic applications. As a powerful experimental method with high time resolution, ultrafast laser spectroscopy has been used to study two-dimensional materials by many groups worldwide. Several topics will be discussed in this seminar. First, we will present studies of nonlinear optical properties of two-dimensional materials, such as second harmonic generation and two-photon absorption. The former allows detection of the crystal orientation and symmetry of two-dimensional monolayers while the latter can measure the optical bandgap of exciton binding energy of two-dimensional materials. Second, transient absorption microscopy technique will be discussed, which has been used to study photocarrier and exciton dynamics. Third, all-optical injection of ballistic currents in ReS₂ studies of the ballistic charge transport will be introduced. Fourth, by performing transient absorption measurements with polarization resolution, spin and valley dynamics of excitons will be discussed. Finally, by performing transient absorption measurements with layer selectivity, we revealed ultrafast electron transfer in hetero-materials formed by stacking two or more two-dimensional materials together. These ultrafast laser measurements of two-dimensional materials and their heterostructures revealed fundamental electronic and optical properties of these materials that are important for their applications as new forms of functional materials.

报告人简介：

赵辉教授于1990-2000年就读于北京交通大学并于2000年获得博士学位。其后在德国的卡尔斯鲁厄大学和美国的爱荷华大学从事博士后研究。2007年起任职美国堪萨斯大学物理与天文学系，2010年获美国国家科学基金会CAREER奖，2017年晋升为正教授。赵辉教授的研究方向为纳米材料的激光光谱学。近年来主要从事二维材料超快激光光谱学的研究，在国际权威刊物发表论文近百篇，研究成果多次被美国国家科学基金会以及多家媒体作为研究亮点报道。最近5年在重要的国际学术会议上做邀请报告20余次，并应邀访问30余家国际知名的大学及研究机构。担任包括自然，自然子刊，物理评论快报，先进材料，纳米快报等40多种国际权威刊物的审稿人和美国、法国、德国、新加坡等国家科研基金的评审专家。

邀请人： 王倜 研究员