Séminaire : « Metasurfaces design as functional absorbers »

Abstract : In recent years, metasurfaces have become one of the research hot topics. Metasurfaces, usually presenting unique micro- or nano-structures, are artificially functional materials which need specific design. In this presentation, we will talk about the variety of metasurfaces according to different classifications and their corresponding design schemes. Among the various metasurface structures, we would like to mainly focus on the broadband and frequency-selective absorbers. The state-of-the-art of absorption metasurfaces will be introduced, as well as their working principles and applications. Then, a kind of ingenious application of metasurfaces will be discussed, namely, the daytime radiative cooling surfaces which should possess highly absorptivity in the atmospheric window, and highly reflectivity in solar spectrum. Finally, a promising candidate metasurface with unique surface morphology-black silicon, will be presented since its excellent absorptivity in ultra-broadband wavelengths. The efforts on designing modified black silicon will be also introduced, in attempt to better satisfy the optical requirements for daytime radiative cooling.

Bio : Xiaoyi Liu is currently a postdoc in ESIEE Paris, ESYCOM Lab, CNRS, Univ Gustave Eiffel. He joined the lab and started his postdoc work from 2019, and was supported by the Chair Blaise Pascal of École Normale Supérieure Fondation. He obtained his Bachelor degree from Shandong University in 2013, and obtained his PhD degree from University of the Chinese Academy of Sciences, Changchun Institute of Optics, Fine Mechanics and Physics in 2018. He focuses on the investigations on high quality Si-based structures and devices based upon surface plasmon polaritons. During his PhD, he won several honors such as the National Scholarship for Postgraduate Students (2015&2017), Special Prize of Daheng Optical Scholarship (2017), Special Prize of President Scholarship of Chinese Academy of Sciences (2018), Excellent Graduate Student of Beijing University of the Chinese Academy of Sciences (2018), Wang Daheng Optical Scholarship for students (2018), Outstanding Doctoral Dissertations of Chinese Academy of Sciences (2019), etc.