Rigorous Analysis of Nanopillar Metasurface Building Block

With advanced fabrication techniques, people have demonstrated metalenses for visible wavelengths with high numerical apertures. A metalens is usually constructed with spatially varying nanostructures as its building blocks. In this example, we analyze the nanopillar structure which is used to compose polarization-insensitive metalenses. With the Fourier modal method (FMM, also known as RCWA), the amplitude and phase transmission of such nanopillars are calculated rigorously.