Abstract
Two-dimensional photonic crystals (2D PhCs) are nanostructure arrays arranged periodically or quasi-periodically, holding great promise as components for integrated and on-chip photonic platforms. The 2D PhCs can be considered as a special type of metasurfaces with periodicity, exhibiting versatile capabilities in the manipulation of electromagnetic waves. In this chapter, we present a summary of recent research trends and challenges related to the application of 2D PhCs as metasurfaces. Initially, we introduce the concepts and principles of Mie resonance, bound states in the continuum, and Fano resonance. Subsequently, we delve into some of the significant applications of 2D-PhC meta-systems, namely structural color generation, polarization manipulation and holography, reviewing their respective advancements. Finally, we offer an outlook on the challenges and potential future developments of 2D-PhC meta-systems to provide guidance for future investigations.