Multifunctional, active and nonlinear optical smart metasurfaces

• Applicant: Professor Dr. Thomas Zentgraf
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2019 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 410406686

Smart planar systems that can perform a number of concurrent tasks and actively control the linear and nonlinear optical response with compact footprint are highly on-demand in current optics and nanophotonics research. The proposed project will build on recent developments in the field of optical metasurfaces. Such metasurfaces are assembled artificial ultrathin sub-wavelength building blocks capable of achieving comprehensive and unprecedented electromagnetic response. Recently, it has been shown that metasurfaces can readily be used for altering the beam propagation of light, as beam shaping elements, and for encoding information. However, there are still several challenges facing metasurfaces, especially for complex anisotropic structures and cascaded layers, which require extra efforts by considering numerous electro-magnetic coupling responses and various resonance phenomena. Only by understanding these effects and their influence on the optical properties can provide a clear physical picture and would allow for a straightforward efficient design. This project aims at theoretical and experimental studies of smart metasurfaces with multifunctional, active, linear and nonlinear properties that can surpass traditional optical elements. In order to attain metasurfaces with custom-designed multi-tasks and active optical characteristics, theoretical models have to be developed and judiciously engineered integrations of functional or active materials must be realized. For increasing the functionality of optical metasurfaces, we will target the problem of simultaneous modulation of multiple beam parameters and the adaption of parallel multiplexing algorithms. Our goal is the development of metasurfaces made of meta-atoms that can alter more than one property of the passing light, e.g. polarization, phase, and amplitude simultaneously, at the time. In addition, to gain access to the dynamical modulation of properties of metasurfaces we will utilize active materials in the design of the meta-atoms that can alter their properties by an external stimulus. The project has been organized into four main thrusts that focus on fundamental mechanisms, deep learning for faster design, multi-functionality and active control of linear and nonlinear effects, which can provide significant gains for future applications. All four thrusts are outlaid to be synergistic and cross-cutting. The techniques and algorithms developed within this project will be combined into a single shared system/device to enhance overall performance and enable smart optical elements. This collaborative project combines the expertise from two groups at Paderborn University and Beijing Institute of Technology in nanophotonics, diffractive optics, holography, and nonlinear optics research, to carry out innovative research for ultra-compact smart metasurfaces.

• DFG Programme: Research Grants
• International Connection: China
• Partner Organisation: National Natural Science Foundation of China
• Cooperation Partner: Professorin Dr. Lingling Huang