Multifocal graphene metalens with a complete field of view for multi-magnification broadband imaging

This is the authors' abstract. We don't add key points for this paper.

Ultrathin multifocal lenses offer a promising route toward compact and highly integrated optical systems. Spatial multiplexing is one of the most straightforward and flexible methods for generating multiple focal spots. However, the field of view (FOV) of each focal channel is typically incomplete due to aperture partitioning, where only a fraction of the lens aperture is allocated to each channel, thereby limiting its applications in integrated optical systems. Here, we explore the possibility of using a single ultrathin graphene metalens (GML) to overcome this limitation. A superposition-based multifocal GML with a complete FOV is proposed by exploiting the subwavelength feature size and stackable nature of GML structures and fabricated using a one-step laser nanoprinting method. A trifocal GML is experimentally demonstrated, enabling clear imaging with variable magnification and subwavelength resolution, while maintaining a complete FOV of 4.636° across the visible spectrum. This work provides a promising strategy for developing multifunctional ultrathin optical components and may facilitate the realization of highly integrated and miniaturized optical systems.