讲座题目：光反射在研究固体表面上的应用

主 讲 人：朱湘东教授

讲座时间：2018年3月19日下午3点

讲座地点：理学院202报告厅

欢迎专业相关或有兴趣的师生前来学习交流！

                                                        理学院

   2018年3月16日

内容简介：

In life sciences and medicine, changes in light transmission, reflection, and emission are exploited in laboratories to characterize properties of biological samples. Seeing is believing. Advances in light-based technology for life science continue to flourish and enable us to see better, learn deeper, and become more informed at faster rates. In this talk, I will describe an example of using light reflection to perform measurements of a large number of biomolecular reactions on solid supports without fluorescence tags. Such a method has enabled us to measure endpoints of biomolecular reactions and observe them in real-time.

On a totally different front, how properties of a solid material transforms under the operation of time reversal is one of the most important characteristics of such a material. In many cases the time-reversal symmetry is an order parameter that characterizes phases of solid materials. Magnets are examples that have no time reversal symmetry. The time-reversal symmetry breaking (TRSB) in materials can be detected optically as these effects alter the polarization state of light (the magneto-optic effect). Optical detection has many advantages such as high spatial resolution, high time resolution, and in-situ detection (See it as it happens), and being easily applicable under a wide range of conditions. Yet birefringence effects that preserve the time reversal symmetry easily overwhelm the magneto-optic effect. I show that Sagnac interferometry is a highly effective means for detecting a TRSB effect as it dramatically suppresses birefringence effects that have time reversal symmetry.

主讲人简介：

  朱湘东教授，现任加州大学戴维斯分校物理系教授。1982年本科毕业于北京大学物理系。1981年入加州大学伯克利分校攻读实验凝聚态物理。1989年获物理博士。同年受聘于加州大学戴维斯分校物理系做助教授。1993年升副教授。1998年升正教授。2001年起任中科院物理所光学实验室客座教授。2007年选入美国物理学会会士（Fellow of American Physical Society）。2011年选入美国光学学会会士（Fellow of Optical Society of America）。多年从事表面物理和光学物理方面的工作。从2000年开始生物物理方面的工作。主要发明了一种特殊的椭偏测量方法（光反射差法）并以此为基础开发了一个高通量，无标记的生物化学反应测量平台。此平台被用于分子生物物理和生物化学方面的基本研究和小分子及生物医药开发。最近两年发明了斜入射Sagnac光干射方法，并开始用这个实验方法研究非常态固体材料包括拓扑绝缘体里表征固体相的磁特征磁和微磁测量。