Metamaterial which are made of sub-wavelength resonant structures have drew enormous attention from physicists and engineers these years because their ability to control wave propagation at sub-wavelength scale which has promising applications in areas such as super-resolution in imaging, cloaking and novel optical and phononic devices. In this talk, we consider the resonant scattering by different types of sub-wavelength resonators, including Helmholtz resonators, plasmonic nanoparticles and air bubbles. In each example, we derive the asymptotic for the resonances. Moreover, we show their applications in super-focusing of wave field, which is to break the Abbe’s diffraction limit, and metasurfaces which is to control propagation of wave field by change of boundary conditions.

Hai Zhang graduated from Wuhan University in 2006. He obtained his Mater degree from the Chinese University of HK in 2009, and his PhD degree from Michigan State University in 2013, all in mathematics. He did a two-year Postdoc afterward at Ecole Normale Superieure in Paris. He joined HKUST as a tenure track Assistant Professor in 2015. Hai Zhang’s main research interest are wave propagation and scattering theory and their applications in material science, inverse problems and imaging. He has published more than ten research papers in top math Journals, including JAMS, CMP, TAMS, RAMA, etc.