講座名稱：Design of optical metasurfaces for innovative display devices

講座時間：2019-11-05 10:30:00

講座地點：南校區G-240

講座人：Boris Gralak

講座人介紹：

B. Gralak于1997年畢業于法國高等理工學院， 2001年與2010年分別獲得了Aix-Marseille大學的博士學位和HDR。B. Gralak目前是CNRS-馬賽菲涅爾實驗室的高級研究員（科研總監），擔任EPSILON研究組負責人，菲涅爾實驗室 “電磁學和超材料”研究組負責人，CNRS-GDR Ondes（http://gdr-ondes.cnrs.fr/）GT1“理論與數值建模”研究組負責人，中法國際光子研究網絡CNRS的IRN PHOTONET（http://www.photonet.cnrs.fr/）法方代表。在國際同行評審期刊上發表55多篇論文。主要的科學貢獻包括有光子晶體中負折射率的第一個數值證明[J. Opt. Soc.Am. A 17，1012（2000）]，第一個熱發射掃描隧道顯微鏡的數值驗證[Nature 444，740（2006）]，超材料吸收和色散特性分析[J. Math. Phys. 51, 052902 (2010); J. Math. Phys. 58, 071501 (2017)]，光學設備的設計：防反射光柵，不可逆設備，平板透鏡，隱形地毯，用于過濾的光柵等。

講座內容：

In this presentation, we report the modeling, the design and the fabrication of transparent and flat optical surfaces which may find applications such as innovative display devices. A finite element method is used to model metallic nanoparticle gratings and to design efficient filters with polarization dependent properties together with high transparency over the visible range [1]. The color of the reflected light is controlled by exploiting the plasmonic resonance frequency which is determined by the size of the nanoparticles [1, 2]. The transparency of the device is governed by the density of nanoparticles and then it can be improved by decreasing this density, i.e. by increasing the lattice constant of the grating array. In order to prevent the optical surface from diffraction when the distance between nanoparticles is large, it is proposed to consider random arrangements of nanoparticles with a given inter-particle average distance. This original idea allows the design of structures with low densities, i.e. with long average distance between nanoparticles, which are likely to present non-specular diffraction orders in visible range. The quality of the transparency, obtained thanks to these low densities of nanoparticles, offers the possibility to use the proposed flat optical surfaces as transparent display devices. These promising results pave the way for head-up-display systems and could find some innovative applications in the transport industry such as in the automotive or aeronautic sectors for displays.

主辦單位：空間科學與技術學院