5月16日 光学讲座信息两则：U Colorado的尹晓波教授和 U Wisconsin-Madison的喻宗夫教授时 间：2014年5月16日 (星期五) 下午2:00-5:00 地 点：唐仲英楼 B501 题 目：When Structured Light Meets Structured Matter at the Nanoscale 报告人：Xiaobo Yin （尹晓波） Materials Science and Engineering Mechanical Engineering University of Colorado Boulder 摘要:This talk will be focusing on how judiciously designed nanostructures and materials can tailor and eventually control the light-matter interactions at the deep-sub-wavelength scale. Dr.Yin will illustrate these design principles by using specific examples. In particular, he will elaborate the strategies to harvest substantial amount of energy-efficient emissions from a sub-wavelength laser cavity and to achieve close-to-unit utilization of light, providing coherent sources at the nanoscale. Also，he will discuss some of the preliminary assessments of the observed valley physics and illustrate the structure and function relationship in these impactful materials that have been widely utilized in both mechanical systems and energy sciences. 题 目：Engineering Thermal Emission with Nanostructures: Thermal Extraction and Superradiant Thermal Emission 报告人：Zongfu Yu（喻宗夫） Department of Electrical and Computer Engineering University of Wisconsin - Madison 摘要: The control of thermal radiation is of great current importance for applications such as energy conversions and radiative cooling. Here Dr.Yu shows theoretically that the thermal emission of a finite-size blackbody emitter can be enhanced in a thermal extraction scheme, where one places the emitter in optical contact with an extraction device consisting of a transparent object, as long as both the emitter and the extraction device have an internal density of state higher than vacuum, and the extraction device has an area larger than the emitter and moreover has a geometry that enables light extraction. The second part of the talk focuses on superradiant thermal emission. The superradiant state reduces the lifetime of a collection of excited atom, which leads to enhanced spontaneous emission that scales as N2 with the number of emitters N. Superradiant emission will be discussed for thermal emitters consisting of optical nanoresonators. In contrast to excited quantum emitters, the superradiant state decreases the emission power from thermal emitters, by a factor as much as 1/N. The suppressed emission is caused by the reduced lifetime of nanoresonators as a result of the superradiant in-phase oscillation of thermal emitters. . |
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电话：+86 25 83592756 传真：+86 25 83595535
