Metalens with invariant size nanocylinders

Recent developments in optical metasurfaces allow for arbitrary control over the phase, transmission, and polarization of light. Flat optics consists of arrays of subwavelength structures that, by spatially varying their size, shape, or orientation on a thin substrate, achieve the desired optical functionality. For example, polarization-insensitive dielectric metalenses focus light by spatially varying the diameter of nanoposts across the metasurface. We present a novel concept to provide phase control while maintaining constant nanopost sizes, while varying only the period, or the spacing between adjacent dielectric nanorods. We demonstrate that such metasurfaces can achieve the desired phase shift behavior and high transmission. We explore this new metasurface concept by simulating a metalens with a hyperbolic phase profile, demonstrating its high optical performance and highlighting its potential for easier fabrication due to the spatially invariant size of the nanocylinders.