Tailoring Light with Layered and Moiré Metasurfaces

Optical metasurfaces are assemblies of subwavelength, artificially designed inclusions forming planarized devices with unprecedented capabilities to manipulate electromagnetic waves and facilitate multiple functionalities. Recent topical efforts in this research area have been focused on pushing forward the frontiers of enhanced light–matter interactions exploiting new concepts and fabrication capabilities. In this context, layered and twisted metasurfaces have showcased interesting features, including flexibility and tunability in manipulating light, contributing to the development of moiré physics for light. Here, we provide an overview on the state-of-art layered and stacked moiré metasurfaces. Free-space multifunctional metadevices are first discussed, followed by recent discoveries in polaritonics and twistronics for twisted hyperbolic metasurface bilayers. We conclude with a discussion on recent advances in the nanofabrication of moiré metasurfaces and remark on their future potential applications.