报告题目：Nanophotonics with Metasurface-Loaded Low-Dimensional Nanomaterials
报 告 人：Guangwei Hu (Department of Electrical and Computer Engineering, National University of Singapore)
报告摘要：“God made the bulk; surfaces were invented by the devil.” Quoted from Wolfgang Pauli. In last two decades, two kinds of surfaces, i.e. metasurfaces (“2D metamaterials”) and low-dimensional nanomaterials (2D materials), emerge and support the extreme manipulation of light within an ultrathin and highly compact platform. However, the development of metasurface reaches a stage where all conventional materials (dielectrics, metals etc) have mostly been exhausted. While 2D nanomaterials presents exotic properties, they are too thin to be practically useful . In this talk, I will show you how we can develop nanophotonics in metasurface-loaded 2D materials, i.e. combining those two “devil-invented” surfaces, via our proposed two important strategies: integration and structuring. Specifically, I will provide a case study of integrating a monolayer semiconductor with a linear metasurface to develop the coherent nonlinear and valleytronic devices , which are not allowed by either metasurfaces or 2D materials alone. Besides, through structuring low-dimensional nanomaterials with a twisted stack, we achieved extreme dispersion engineering and “magic-angle” topological transitions of plasmon  and phonon polaritons . This work, for the first time, has transformed the so-called twistronics (i.e. engineering electron’s bandstructures of interlayer-coupled twisted 2D materials in condensed matter physics) into photonic regime and developed the new field of “opto-twistronics”. Via the proposed systematic strategies of integration and structuring, the advanced valleytronic, nonlinear, polaritonic and opto-twistronic applications may be developed. Other recent results will also be discussed.
 Z. Dai, G. Hu, et al., "Artificial Metaphotonics Born Naturally in Two Dimensions", Chemical Reviews, 120, 6197 (2020).
 G. Hu, X. Hong et al., "Coherent Steering of Nonlinear Chiral Valley Photons with a Synthetic Au-WS2 Metasurface." Nature Photonics, 13, 467 (2019).
 G. Hu, A. Krasnok, Y. Mazor, C.-W. Qiu, A. Alù, "Moiré Hyperbolic Metasurfaces", Nano Letters, 20, 3217 (2020).
 G. Hu, Q. Ou et al., “Topological Polaritons and Photonic Magic-Angle in Twisted α-MoO3 Bi-Layers”, Nature, 582, 209 (2020)
报告人简介：Dr. Guangwei Hu (胡光维) is a Research Fellow in ECE Department of National University of Singapore (NUS). He obtained PhD degree from NUS in Oct. 2020, mentored by Prof. Cheng-Wei Qiu and Prof. Andrea Alù, and the B.S. from Physics in Harbin Institute Technology in July 2016. His current research interests are developing multiphysics nanophotonic platforms by combining metamaterials/metasurfaces with low-dimensional quantum nanomaterials for nonlinear, valleytronic, polaritonic, topological, twistronic and other new concepts and applications. He has published more than 50 papers, including 3 in Nature (first/co-first author), 1 in Nature Photonics, 4 in Nature Communications, 1 in PRL (corresponding author) and many others. His work has been featured as Top 10 Breakthrough in Physics of 2020, Optics and Photonics News (Year of Optics in 2021), Science and Technology Daily (科技日报) and many others. He received the Rising Star of Light in 2020 by Light: Science & Applications and NUS President’s Graduate Fellowships.