Benfeng BAI, Department of Precision Instrument, Tsinghua University, Beijing, China will give a seminar "Ultra-thin and new-concept optical devices based on metasurfaces" in Room Pierre Cotton, Institut Fresnel on Friday September 4 at 14h00.
Abstract :
Metasurfaces, a class of mono-layered metamaterials, have shown great potential for the control of wavefront without requiring complicated 3D nanofabrication. In this talk, we present our recent works on a new type of Berry-phase metasurface composed of gold nanorod antenna array. Based on the Berry phase modulation principle, the metasurface can produce dispersionless interfacial phase discontinuities under the illumination of circularly polarized light. Since the phase of wavefront can be controlled in each subwavelength unit cell and can be switched by the helicity of incident light, such metasurfaces show some special properties such as dispersionless phase modulation, helicity-switching, and the separate modulation of phase and amplitude. Several novel functionalities based on this metasurface are demonstrated, including the anomalous refraction of light, the generation of broadband vortex beam, the dual-polarity metalenses, the helicity-switchable unidirectional SPP launcher, and 3D holographic display, which function in visible to near-IR regime. Such ultra-thin metasurfaces may pave the way towards novel nano-devices for beam shaping, data storage, optical information processing, holography-based techniques and so on.
Biography :
Prof. Benfeng Bai received his B.Sc. degree and Ph.D degree in Optical Engineering from Tsinghua University, China, in 2001 and 2006, respectively. He is now leading a nanophotonics research group in the Department of Precision Instrument, Tsinghua University, China. His research interests focus on plasmonics, metamaterials, and optical measurement technologies based on nanophotonics. He has published more than 50 research papers in international journals including Nature Commun., Light : Sci. & Appl., Nano Lett., Small, etc. He is currently a member of the Nano-characterization Technology Standardization Working Group of the National Nanotechnology Standardization Committee of China. He is also serving as a Topical Editor for Optics Letters since March, 2014.
Contact : Benfeng BAI, Tsinghua University baibenfeng@tsinghua.edu.cn
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