Abstract
Metamaterials have attracted tremendous attention due to their exotic optical properties and functionalities that are not attainable from naturally occurring materials. In particular, metamaterials can be designed to introduce strong spin-orbit coupling for light. In this presentation, I will talk about controlling spin-orbit coupling of light using 2D metasurfaces and 3D metamaterials. I will start with geometric metasurfaces, a unique type of structured surfaces showing spin-dependent abrupt phase discontinuities arising from the pancharatnam-Berry (geometric) phase [1-4]. I will further show that extending the concept of PB phase to harmonic generations can lead to continuous phase control over the local nonlinear polarizability, which goes beyond the binary modulation of nonlinearity with the conventional poling techniques [5]. In the second part of my talk, I will discuss topological orders in metamaterials and consequently topologically protected photonic surface states that are immune from scattering by sharp edges [6]. Gauge field is created through inhomogeneous design of the Weyl metamaterial, which leads to observation of one-way propagating bulk chiral zero mode.
References:
1. L. Huang , X. Chen , H. Mühlenbernd , G. Li , B. Bai , Q. Tan , G. Jin , T. Zentgraf , and S. Zhang, , Nano Letters, 12, 5750 (2012)
2. X. Chen, L. Huang, H. Mühlenbernd, G. X. Li, B. Bai, Q. Tan, G. Jin, C. W. Qiu, S. Zhang, and T. Zentgraf, Nature Communications, 3, 1198 (2012)
3. L.L. Huang, X. Chen, H. Muhlenbernd, H. Zhang, S. Chen, B. Bai, Q. Tan, G. Jin, K.-W. Cheah, C.-W. Qiu, J. Li, T. Zentgraf, and S. Zhang, Nature Communications,4, 2808 (2013)
4. G Zheng, H Mühlenbernd, M Kenney, G Li, T Zentgraf and S Zhang, "Metasurface holograms reaching 80% efficiency", Nature Nanotechnology, 10, 308 (2015)
5. G Li, S Chen, N Pholchai, B Reineke, PWH Wong, EYB Pun, KW Cheah, T Zentgraf & S Zhang, "Continuous control of the nonlinearity phase for harmonic generations", Nature Materials, 14, 607 (2015)
6. W Gao, M Lawrence, B Yang, F Liu, F Fang, B Béri, J Li, and S Zhang, Physical Review Letters, 114, 037402
Biography
Professor Shuang Zhang received BS in Physics from Jilin University, China, MS. in Physics from Northeastern University (USA) and Ph.D in Electrical Engineering from the University of New Mexico. From December 2005 to August 2006, he was a Postdoctoral Research Fellow at the University of Illinois at Urbana-Champaign, and from August 2006 to March 2010, he was first a Postdoctoral Research Fellow and later an Assistant Research Engineer at the University of California Berkeley. In March 2010, he took the position of Reader in the School of Physics & Astronomy, University of Birmingham, and was promoted to professor in March, 2013. Professor Zhang is the recipient of IUPAP (International Union of Pure and Applied Physics) Young Scientist Prize in Optics, the Royal Society Wolfson Research Merit Award in 2016. He was elected a Fellow of the Optical Society of America (OSA) in 2016.
Anyone interested is welcome to attend.