LAUSR

Over the last two decades, the capabilities of metasurfaces in light modulation with subwavelength thickness have been proven, and metasurfaces are expected to miniaturize conventional optical components and add various functionalities. In this review article, various metasurface design strategies are reviewed thoroughly. First, we revisit the scalar diffraction theory to provide the basic principle of light propagation. Then, we discuss 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 unit-cell approach. We examine unconventional metasurfaces where the conventional design methods fail and finally discuss potential design methods for such metasurfaces. This article is protected by copyright. All rights reserved.