Samsung Advanced Institute of Technology

Over the last two decades, metasurfaces have proved their capabilities in light modulation with subwavelength thickness, and they are expected to miniaturize conventional optical components and add various functionalities. In this review article, various metasurface design strategies are reviewed thoroughly. We first revisit the scalar diffraction theory to provide the basic principle of light propagation. Then, we discuss the most widely used design methods based on the unit-cell approach. The methods include a set of simplified steps, including the phase map retrieval and meta-atom unit-cell design. Then, we introduce recently emerging metasurfaces that may not be accurately designed using the unit-cell-based design approach. We examine unconventional metasurfaces where the conventional design methods fail and finally discuss potential design methods for such metasurfaces.