Semi-analytical models to engineer a metalens composed of various meta-atoms

We developed semi-analytical models to efficiently and rapidly obtain the propagation characteristics of square nanopillar and nanoring meta-atoms. We show that such analytical models can predict the output phase profile and chromatic behavior of a metasurface composed of various meta-atoms. We found that said models are accurate enough so that an optical designer can use them as a quick and pertinent alternative to tedious and time-consuming FDTD simulations. A mixed array of three different nanostructures combining square nanopillars, nanorings, and nanorods has been designed and compared to FDTD simulation with good conformity. Thus, we show the pertinence of the two semi-analytical models and the possibilities granted by the mixing of various meta-atoms. This work allows for more flexibility and design freedom for quick modeling of metasurface properties and adds to previous models developed in our research group.