High-Resolution Hexagonal Subpixels Based on Electrically Focus-Tunable Graphene Photosieves

The high demand for high-resolution, compact and electrically focus-tunable flat optics in display applications leads to tremendous research on nanoscale diffractive lenses. Graphene with a unique band structure allows controlling carriers by adjusting the Fermi level under the applied electrical field, which changes the transmission characteristics of graphene. It ultimately facilitates the optical focal tuning effect in the graphene-based lens under the applied electrical field. We demonstrate high-resolution hexagonal subpixels based on the graphene photosieve with electrically tunable focusing that enables to control in pixel units of display applications. A high focusing efficiency at a visible wavelength of 532 nm can be achieved with the photosieve thickness of ~12 nm, and the variation of the focal length  ~10%.